Jump to content


Garage Vehicles

Disney Pics 003.jpg

Jeep Wrangler (1992)

Owner: Megatron

Added: 27 September 2013 - 08:56 AM

20131023_113518.jpg

Dodge Ram 3500 (2006)

Owner: Megatron

Added: 25 September 2013 - 07:37 AM

6-inch XJ suspension lift (Lead).jpg

Jeep XJ Cherokee 4WD Sport 4-door (1999)

Owner: Moses Ludel

Added: 15 September 2013 - 01:16 PM

1988DodgeDakota.jpg

Dodge Dakota (1988)

Owner: biggman100

Added: 22 September 2013 - 05:22 PM

Forum Photos (2).jpg

Dodge Ram 3500 Cummins Quad-Cab 4x4 S...

Owner: Moses Ludel

Added: 15 September 2013 - 08:42 AM


Photo
- - - - -

Avoid Honda XR650R Motorcycle Engine Damage—Use the Correct Main and Pilot Jets!

dirt motorcycle off-road motorcycle dirt bike discussion dirt bike how-to dirt bike troubleshooting thumper motorcycle Honda XR motorcycle backcountry riding

  • Please log in to reply
27 replies to this topic

#1 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 31 December 2013 - 01:22 PM

The magazine recently purchased a 2000 Honda XR650R motorcycle with less than 1000 original miles on the bike. An honest and forthright previous owner could not start the engine, and given the mileage, we agreed that the problem was stale winter (ethanol) fuel—which had eaten up the plastic tank screen! I trailered the cycle home and looked forward to restoring the fuel system and completing the dual-sport conversion process. The motorcycle will be an HD video shooting platform for remote backcountry documentary filming and off-pavement event coverage, so the XR650R's low mileage seemed a huge asset.

 

After 20 hours of prepping the cycle for a Nevada dual-sport inspection, including some minor tuning and checking out the bike's general condition, I discovered that the 650 thumper engine would not start. Consulting two friends with XR650Rs, I assumed that my starting technique was the culprit. A heavy cardio workout later, it was apparent that the compression was lacking. I did a quick compression gauge check and discovered a 95 PSI cranking compression issue. (To assure an accurate reading, make sure the auto-decompression mechanism is not holding the valves open when performing a compression test!)

Attached File  Cylinder Leak Down Test-7.JPG   97.49KB   0 downloadsAttached File  Cylinder Leak Down Test-8.JPG   96.97KB   0 downloadsAttached File  Cylinder Leak Down Test-11.JPG   101.44KB   0 downloadsAttached File  Cylinder Leak Down Test-12.JPG   98.15KB   0 downloads

My next step was a cylinder leak down test, which I have covered in detail with an HD video how-to feature. (Click here to view the HD video how-to procedure and results!)  The leak down test pinpointed leaking intake and exhaust valves; a look inside the cylinder (through the spark plug hole) also indicated scoring at the upper wall of the Nikasil cylinder plating. Time for an upper engine tear down, which I cover as a step-by-step HD video: Click here to see the how-to series at the 4WD Mechanix HD Video Network's freshly launched "The Off-Road Motorcycle Channel".

 

So, how did a "bulletproof" Honda XR650R motorcycle, with less than 1000 miles since new, end up with a worn out set of valves and leaky piston and rings? The answer is two-fold: 1) the motorcycle had an incomplete "uncorking" job with a partial "Honda Power-Up Kit" installed and 2) a leaking aftermarket air filter had seeped abrasive dirt into the air stream and through the engine's intake system. The air filter issue is notorious for pitting valves, scoring an upper cylinder and damaging piston rings on motorcycle and automotive engines. An incomplete uncorking calls attention to an ever important problem for any motorcycle engine modification: the need to re-jet the carburetor to compensate for improved intake flow or a less restrictive exhaust system!

 

The "Power-Up Kit" opened up the exhaust cap on the muffler and reduced exhaust backpressure (basically an HRC end cap). The cycle is a non-California model, so there was no restrictive "D" molding in the intake manifold grommet. (The non-California intake manifold is considered the unrestricted air intake, often sold as the upgrade for better breathing.) The pilot jet had the Power Up Kit's #68 sizing, though not the specific "68s" style. However, for some unfathomable reason, the main jet in place was still the ultra-lean, original 125 main jet!  The most important ingredient in the uncorking process for a Honda XR650R motorcycle engine is the unrestricted rubber intake manifold and a jetting change to a 175 main jet and 68s pilot jet (base line at sea level). Exhaust modifications help further, the stock OE muffler's exit flow and end cap are ridiculously small for a 650 thumper!

 

How important is the 175 main jet and 68s pilot? Important enough to be the OEM jet sizing on all Honda XR650R engines sold outside of North America! The U.S. engines were leaned to the limit by E.P.A. requirements, and California models (XR650R AC designation) were even more restricted by a draconian reshape and air flow restriction in the rubber intake manifold and the intake air box. So, this uncorked, non-California model had its exhaust opened and uncapped—plus the removal of air intake box restrictors. The EPA regulated (non-California) cycle already had the open, round intake manifold. It was in severe need of the 175 main jet, however, which the dealer neglected to install with the power tuning!

Attached File  Honda XR650R Engine Teardown-6.JPG   115.19KB   0 downloadsAttached File  Honda XR650R Engine Teardown-7.JPG   94.12KB   0 downloadsAttached File  Honda XR650R Engine Teardown-8.JPG   92.29KB   0 downloadsAttached File  Honda XR650R Engine Teardown-10.JPG   88.79KB   2 downloads

The result is clear. Despite the low mileage, this engine was busy overheating its upper cylinder and valves. Upon tear down, which you can follow in the HD video linked above, the engine's upper cylinder looked more like a Baja 1000 Race finisher than 1000 miles of reasonable recreational riding. Fortunately, the previous owner had used quality lubricant and changed oil filters regularly. The XR650R's unique liquid cooling (the only XR to ever offer it!) also helped minimize damage and isolate the wear to the cylinder plating, piston skirts, rings and valves. The main engine assembly is still in near-new condition.

 

I'm now in the process of rebuilding the upper engine. The head and cylinder have been sublet to L.A. Sleeve Company. My approach will likely be an alloy iron/chrome/moly, patented L.A. Sleeve liner in place of the factory Nikasil. Though many are fans of Nikasil, I'm not thrilled that's its only a "plating" thick. This Honda XR650R has a lot of work ahead, and it must be ultra reliable.

 

I may consider a Stage 1 Hot Cams alternative, mainly to eliminate the auto-decompression mechanism on the OE camshaft. Compression ratio will remain the stock 10:1 with the new upgrade piston, enough squeeze for higher altitudes and the limit for kick starting and long piston ring life! Quality machine work, a fresh cylinder and upgrade piston choice, renewed valves and proper assembly technique will have this motorcycle living up to its legendary reputation—with a 175 main jet and 68* pilot jet in its Keihin carburetor!  Follow the rebuild how-to coverage at the magazine's The Off-Road Motorcycle Channel—in 1080P HD video!

 

*Note: The carburetor had a straight 68 jet installed, and I will see if the 68s is necessary. There is a difference in the flow between these two varieties. Honda's Power-Up Kit does call for the 68s and also a needle change if necessary. I will fine tune as needed, though that would be anticipated at northern Nevada. Our home base is 4,500 feet elevation and high desert; the average/mean elevation at Nevada is 5,500 feet!

 

Moses



#2 RareCJ8

RareCJ8

    Advanced Member

  • Members
  • PipPipPip
  • 80 posts

Posted 31 December 2013 - 02:13 PM

very interesting stuff moses.   my 650 was already uncorked and unplugged when i bought it, so i have no idea about condition or jetting, etc.  the manual start is a real bugger.  sometimes i get pretty winded just getting it to start, not counting all the times right foot slips off kick start lever  and right foot peg jams into the shin...ouch.  that said, it can sit for months and months and after about 7-8 good kicks, starts right up.  My latest project is to install the front brake re build kit.  seems sitting for a length of time allows air to get sucked into the system leading to no or nearly no front brake.  yikes!  tired of constant bleeding.

 

in other news, took delivery of the uber-cool dual voltage gauge for jeep.  the instructions show it simply hooked direct to the batteries, but i am concerned parasitic draw may pull down those batteries.    will advise and best to all in the new year.


VCMontanaandScramble2013277_zps6b71c866.


#3 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 31 December 2013 - 04:19 PM

RareCj8...A leak down test is spot on and conclusive (see HD video for details). The damage source for my engine was clear when I discovered the 125 OEM main jet in place and dirt around the edge of the air filter.  This cycle had been ridden primarily in Texas (lower elevations) on the lean mixture.

 

Generally understood is that "uncorking" involves a list of changes, which includes the 175 main jet (selection is a no brainer, this is the OE main jet outside the U.S. for engines identical to ours). All of the XR650Rs with the OE main jet are under duress, especially non-California models still running with the original main jet. Uncorking without changing the main and pilot jets becomes the death knell. Here is the "official" Honda Power-Up Kit list of parts plus the removal of the air box restrictors. (This list is third party info and somewhat dated; confirm current part numbers available at your Honda dealership.) The list:

 

 16211-MBN-640 (Insulator, Carburetor, which gets rid of the California "D" shaped restrictor manifold)
 18317-MBN-640 (Exhaust Tip without the tiny outlet and restriction)
 99105-MBN-0680 (68s Pilot Jet)
 99101-357-1750 (Main Jet 175)
 16012-MBN-641 (B53E Needle Set, this is based on tuning needs; at our altitude, try without the needle change first)

 

Also expected is the removal of the "user removable" air box restrictions. A Power Up Kit should not be confused with the Honda Racing kit for the XR650R. The HRC kit adds a warmer camshaft, improved piston and rings with bumped compression (11:1, really?) plus other racing nuances.

 

The OE Keihin pilot and main jet are each accessible with the float bowl removed, and the Keihin carburetor can be carefully rotated to access all four float bowl screws. They are Japanese Phillips head and vulnerable to rounding if not careful, but most of us who have owned Japanese motorcycles have been there and own a hand impact driver for that purpose. 

 

You can access and remove the main jet by simply unscrewing the drain plug at the bottom of the float bowl and accessing the jet with an appropriate 1/4" drive metric socket. This lean issue is serious enough to warrant looking at the installed jet if you're unsure of its size/flow. You and I live at nearly the same altitude, and I opted for a 172 main jet for the 4,500-7,000 foot elevation range that I typically ride. 175 would likely be okay if you want to play it safe for sea level, you should be able to readily run to 6,000 or so feet without fouling a spark plug. When you read the jet change charts, even from Honda, there's a wide range of adjustment for ambient temperature and altitude. My cycle's pilot had been changed to a 68 (not 68s), which I'll try and go from there. I haven't pursued the needle position or type, would bet it's stone stock since the carburetor's top looks unopened. We can discuss fine tuning and carburetor staging later...For others, keep in mind that tuning is altitude and temperature sensitive.

 

As for the voltage meter(s) for the CJ-8 Jeep, I totally agree. We're back to my suggestion that you simply route the lead wire to the voltmeter through a standard Bosch-type relay that is key-on activated. The relay would close the circuit on the wire lead when you turn on the ignition key and open the circuit/lead when you turn off the key. This would deactivate current flow of any kind with the key off. Refer to my primitive drawing (earlier exchange) for ideas.

 

Have a safe and very Happy New Year! We'll ride the Big Red Pigs (XR650s) at the desert when I get this beast plated, I'm looking forward to that prospect!

 

Moses



#4 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 02 July 2014 - 06:13 PM

Hi Moses, have you got an idea about what jets and needles the Euro version of the XR would have come with stock? I'm going to open my carb for maintenance and will be doing some thinking about what should or shouldn't be in there. As you know, my motor (Euro model) is fried from overheating/dirt ingestion/bad maintenance...

 

D.



#5 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 29 July 2014 - 04:41 AM

Hi, David...I've been very busy with Michelin T63 tire testing on the Honda XR650R, you'll enjoy the road testing and also the addition of TCI Products racks and Nelson-Rigg bags...

 

As for jetting, here is a PDF with Euro and Australia specifications:

 

Attached File  Honda XR650R Specifications.pdf   3.71MB   6 downloads

 

You should have a 175 main jet, a 65 pilot jet and the needle clip in the third groove from the top.  You'll see this listed by market in the specs.  Also, I included many of the other detail specs that you might find useful to your project.

 

Thanks for posting, I'm back from the tests and HD video filming, so my responses will be timely.  You'll get a real kick out of the off-pavement and on-pavement testing.  Stay tuned, I'll be doing the post production video edit work this week!

 

Moses

 

 



#6 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 09 August 2014 - 05:30 AM

Hi Moses,

 

I've now had a chance to go through the posts - thanks for the responses! The spec sheet is gonna come in very handy!

 

As far as jetting is concerned, I may have mentioned that I ordered a Moose Racing repair kit off a French website, hoping it would have the correct jets in it. Although the kit came with the 65 pilot, it does not have the 175 main in it (I think it was a 150 or less). So I have gone to HondaParts-Direct and ordered the 175 which I will receive here in the US (I arrived yesterday) to take back with me.

 

But I was just wondering - in other words I'm asking for input :) - about jetting. The higher the number on the jet in this case, the more fuel it's flowing, right? And the higher the altitude, the less fuel you want flowing (to maintain the right air/fuel ratio), right? Same goes for when it's hotter, right? If so, this leads me to believe that for my application at 3,000-6,000 ft. in average daytime temps of about 80 Fahrenheit, I should go leaner than 175. Anyway, when I open the carb, I'll see what was in it originally and take it from there.

 

One problem I'm going to have to deal with is a seized mixture screw (the one that goes horizontally into the carb body). Not only is it seized but there's not much of a head left on it - and it's recessed into a hole of sorts, making it impossible to grab with a pair of pliers... So I don't have any bright ideas on how to get it out - much less how to adjust it! If I knew what it was set at (how many turns out), I could just leave it alone, but I doubt that it is adjusted correctly. Phooey.

 

D.



#7 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 09 August 2014 - 04:02 PM

You're right about jet numbers and sizing, David.  We're based at 4,300 feet elevation, and most of my riding is between 4,000-7,000 feet elevation.  A 175 main jet is for sea level.  Typically, you would gradually taper down, proportionately, especially for altitudes above 5,000 foot range.  Ambient temperature is also a critical factor, so pay close attention to both altitude and temperature!

 

I've attached an older Honda workshop recommendation for my 1984 Honda XR350R that should clarify the goals here.  (The later manuals are remiss about much of this logic, apparently too busy appeasing exhaust emission regulatory agencies.)  1984 was still an era when getting a dirt motorcycle engine to run right and last a long time held priority.  Disregard the XR350R model-specific info, you're interested in the chart and the explanation of how to use the chart and do the math, which is actually quite simple:

 

Attached File  Honda Carburetor Jetting for Altitude.pdf   732.23KB   8 downloads

 

In the real world, I'm loading my bike with gear.  Just added TCI Products racks and skid protection with Nelson-Rigg bags, check out the magazine article and HD videos.  I can find myself riding at the lower desert around Moab and Southern California events.  (The Moab Area can provide a range of 4,000-6500 feet, possibly more at the La Sal Range.)  My XR650R carries added weight and will soon have a larger fuel tank, too.  I also have the Hot Cams Stage 1 camshaft, which eliminates the auto-decompression start mechanism on the stock camshaft and has been an absolute joy in real world riding gains.

 

All of that said, I strive for a balance here, plus realism about not having to change jets every time I go somewhere.  For the main jet, I opted for a 172.  For the pilot, I intentionally installed the less efficient straight 68 (not a 68S).  I get the flow rate but not the "better emulsified" fuel.  The needle clip is 3rd position from top.  The engine is faithfully and thoroughly "uncorked" to Honda 'Power-Up Kit' standards as well.  I had to complete this upgrade, as the previous owner did not, and the engine was suffering prior to the top end rebuild.  Your European market engine (stock) should have each of these modifications in its original form.  We can confirm.  Here is the Honda "factory" N.A. Power-Up Kit (not the all-out racing HRC kit) parts list:

 

Attached File  Honda Factory Power Up Kit Part Numbers.txt   432bytes   3 downloads

 

Why did I start with these specs?  My reasoning: I'm not going to change jets for Moab, Utah (4,025 feet in town) or King of the Hammers at Johnson Valley, CA (2,300-4,600 feet elevation range).  The 172 is conservative, slightly lean from a 175, rich enough for running at sea level without risk of holing a piston.  (Much more considerate than Honda's draconian 125 main jet in North American engines, detuning the engine just to run with this ridiculously lean jet!)  So, the remaining question is higher altitudes, and here's my experience to date.  Accept this as my experience and equipment.

 

The engine runs very strongly from idle to redline, without blubber, hesitation or anything other than a fast ride.  (See my Michelin road test 'Part 2' video for living proof.)  It pulls incredibly well, with excellent transitions from curb idle through midrange to redline.  The spark plug color looks great, a very good indicator of a single cylinder motorcycle engine's combustion process and air/fuel ratio

 

As for starting, first let me emphasize that I use the manual compression release lever.  Here's my approach:

 

1) I bring the piston to compression pressure (leading to TDC), then pull in the release lever and push over TDC just slightly with the kick starter before attempting to kick down.

 

2) Over TDC slightly, I firmly kick through (not with extreme force other than to overcome the needs of a 10:1 compression engine).  I can get the engine to start most often on the first or second kick, at worst, the third kick.

 

3) Here is the capper:  I avoid use of heavy choking.  If completely cold, I either place the choke on half-choke or full choke for just a few kicks with the ignition turned off and compression release lever pulled in. 

 

5) The throttle stays closed until actual engine firing, then gets blipped slightly, immediately, to let the engine breath and keep running. If cold-blooded, the throttle is held slightly open to let the engine stabilize. 

 

4) If I fire the engine with the choke on full, it must immediately be stepped down to middle position or even off (warm ambient temps now around 75 degrees F when I start the bike).  For a hardcore, subfreezing Nevada winter at 4,300 feet, I anticipate playing up the choke enrichment. 

 

5) As soon as the engine is running, I open the choke lever fully.  If I happen to get overly zealous with the choke and create a hard start or stall upon starting, I turn off the ignition, pull in the compression release lever, hold the throttle well open, and kick through 4-5 times to clean out the cylinder.  Then I start over again.

 

This starting thing for the XR650R is apparently an issue.  Many follow elaborate regimens to get the engine to fire.  Personally, I believe they must be over-fueling or over-choking the engine.  Choke opened immediately, I can get my engine to idle stably within a 1/4- to 1/2-mile of riding this time of year. 

 

I do exert caution when the engine is cold while riding with the choke open.  The engine is lean, and I can feel it wanting slightly more fuel, which I provide with throttle instead of the choke. 

 

Keep in mind that the main jet size has virtually no impact on idle.  The pilot jet does, however, and it also affects the lower speed throttle transitions.  Of course, the idle mixture screw circuit has the largest impact with the stock carburetor design.  I must say that other than the idle speed when cold with the choke completely off, my engine responds wonderfully, both hot and cold. 

 

I compensate for the open choke until the engine warms.  This is just my approach, I don't like over-fueling the engine during its warm-up cycle.  Some don't mind.  The tip-off for me is that the bike can be immediately ridden with the choke off, without hesitating, faltering or stalling—as long as I work the throttle slightly when coming to a complete stop and idle.

 

You may need or benefit from a leaner main jet at your altitude and engine tune, but this can only be tested at higher rpm with the engine's performance under open throttle.  Lower speeds, you're more concerned with the pilot, and a 65, which is stock for North America, apparently is all Moose can provide.  Sounds like they're emission constrained and not into the "Honda Power Up" kit approach, which is readily available through dealerships as "off-highway" use as you discovered. This is Catch-22, since the N.A. bike was not authorized for highway use, according to California and EPA, yet you can jet for better off-highway performance!  And Honda is the guideline we use here, its Power-Up Kit part numbers include the 175 main, 68(S) pilot and the change in needle and seat.

 

The needle and seat change is not as crucial as the needle position, which should be 3rd clip position (from the top) for starters.  This is an easy road test, as the transitions from a closed to open throttle, including abrupt throttle changes, will indicate the correctness or shortfalls of the pilot jet size and needle position.  We can talk about this when you get the bike on the road. 

 

For me, I took an educated guess and accounted for the improved breathing of the Power-Up part numbers, including the exhaust tip which you can see in the Nelson-Rigg/TCI Products coverage, and my camshaft change.  I have the non-California, round inside intake grommet between the carburetor and the cylinder head, too.  This was stock, as the bike, fortunately, was original sold in Texas.  I have none of the California emissions pump paraphernalia, which pops up in distinctions between the XR650A and XR650AC parts listings. 

 

AC is a California designated engine that deserves great sympathy.  When you have the time on one of your online searches for part numbers, check out the distinctions and schematics for the AC versus straight A models.  Here are the primary pieces you should not find on your European XR650R (not OEM on my cycle, either, fortunately) that California buyers will be chasing down for years to come: http://www.hondapart...uction-valve-ac

 

The other key AC pieces were the extreme exhaust tip restriction, narrowed passage intake grommet, restricted air box and jetting restrictions.  Some of these items carry over to the "A" models as well.  After the complete 'Power-Up Kit' upgrade, my engine is like yours should be, with the stock, non-California round type intake grommet, larger exhaust tip piping, unrestricted air box (yours might have the restrictors still) and proper jetting.  You might share photos of your stock Euro equipment.  N.A. members and guests would find that interesting.

 

I am very curious what your stock jetting turns out to be, including the main and pilot plus the needle clip position.  A light rebuild is a wonderful treat for these carburetors, and judging by your idle mixture screw, perhaps you'll be lucky, and nobody damaged the rest of the carburetor.  The idle screw is readily available, on my used model that was an item I replaced.  The very fine tip needs extreme care when installing the screw.  If off-center, that tip will bend in a wink.  Do not force the screw into position, you'd be guaranteed trouble!  When you remove the idle mixture screw, the tip size will be clear.

 

As for removing the damaged screw, there are several approaches here.  Since you'll have the carburetor off anyway, you can carefully drill the center of the screw head with a smaller bit. If you have a drill motor than can be reversed, a left hand drill bit will often spin a screw loose while you're attempting to drill the hole.  If not, use care not to damage the threaded portion of the carburetor body, and spend some time with a drill and tiny easy-out, removing the mixture screw once you can get the easy-out into the drilled hole.

 

Let's keep this discussion going.  I'd like to know your findings, your conclusions and your experience with both the jetting and the starting technique.  I don't believe that any properly tuned engine should be "hard to start".  These engines are sensitive only due to one cylinder and lots of compression.  Make friends with your engine's particular starting preferences.  Mine work for me, I can start the engine cold or hot on one to three kicks maximum.  That's actually better than the Baja racing versions of these engines. 

 

My favorite cult classic XR650R movie, "Dust to Glory", shows how race positions actually change during a pit restart.  Andy Grider has just outpaced Johnny Campbell in an epic battle between pits and hands over his bike to the next Honda B Team rider.  The B Team rider can't get the XR650R to fire promptly, and the A Team rider sails by...Good tale about the XR650R and hard starting, but don't let this get you down.  With proper tuning and conservative use of the choke, anyone can share my experience.

 

Note: As for starting thumper motorcycles, this XR650R is not my first rodeo.  I teethed on a '69 BSA Victor 441 and owned three Honda XR enduro bikes prior to the XR650R.  Granted, the XR650R is the beast of the bunch, yet starting the engine should be the least of the rider's challenges.

 

As for setting the idle screw, 1-1/2 to 1-3/4 turns from lightly seated is a nice place to start at your altitude.  Give that a go, you'll make fine adjustment with the engine completely warmed.  Again, I go for just enough enrichment for a very smooth and stable idle, nothing more or less.  I've only touched the mixture screw one time since initial adjustment.  Here is the factory procedure, your best guideline:

 

Attached File  Honda XR650R Idle Mix Setting.pdf   230.03KB   4 downloads 

 

Many owners like to fiddle endlessly with the idle speed screw, adjusting it up and down regularly.  I stopped following this myth by concentrating on stabilizing the engine with the hand throttle on the extremely rare occasions when the engine seems hesitant to idle.  Create stability by using your hand throttle, gently blipping (no major rpm changes, please, this is not a premix two-stroke!) or holding steady at a slightly higher rpm than curb idle for a moment—until the engine cleans out and temperatures stabilize.  With steady air and fuel flow, and coolant temperature stability, the XR650R will want to idle smoothly again—even with its stock ignition and OE carburetor.

 

As you gain confidence in the engine, its tune and your skillful carburetor rebuild and adjustment, this will get easier.  If you set the carburetor to factory recommendations in each area, including float height, you should have a much less finicky engine.  Don't race off to buy a $700 replacement carburetor just yet!

 

Moses



#8 fullchoke

fullchoke

    Advanced Member

  • Members
  • PipPipPip
  • 13 posts

Posted 10 August 2014 - 05:30 PM

Hi Moses, I subscribed once I read your posts in this thread. I'm sorry to read about your misfortune with your xr650r. I just bought an 2000 XR650r a couple of days ago, I have no prior experience with them. I'm an old rider, I too used to ride a BSA B50 and have a 1982 XR500r and a 1984 XR350R. I've been trying to figure out if my bike has been "uncorked" as they call it. The prior owner knew nothing about any mods. The exhaust is not restricted. I pulled the main jet and it is a 145RD. The prior owner was satisfied with the performance, none of his friends could keep up with him. The rear sprocket was changed to lower the gearing for trails, so it probably was not ridden at WOT too much. That is what I'm hoping. Before I started the bike when I got it home I found the air filter leaking dust, so I have not ridden it yet. The rubber boot was still in the airbox but the plastic is not. While the filter is being shipped I have delved into the uncorking of my bike or lack thereof. Until I read your post I could not find anything definite about the stock jetting. The Moose kit has raised my brow as to the 145RD jet in mine. I just pulled the carb and there is no restriction in the manifold. This bike was sold new in Seattle. When my jets arrive I'll disassemble the carb and see what else is in there. Thanks for your informative post. I hope other xr650r owners will post what they found in their bikes before they "uncorked" their BRP.

 

Greg



#9 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 10 August 2014 - 10:39 PM

Hi, fullchoke...We do have a lot in common!  Wow, what are the odds, we each had BSA singles and XR350R and 500R models.  Each of my air-cooled XRs are 1984 models.  We sold the '83 XR200R when our youngest son went to college in 1999 or would otherwise still have it, too.  He's coming around to dirt riding again, and we recently found him a buy on a 2003 XR400R, 134 actual miles on the odometer, essentially a brand new bike!

 

Thanks for your concern about the work I needed to do on the XR650R.  The previous owner was quite fair, there was relief for the expenses I encountered, and frankly, I'm now pleased that the top-end rebuild is done.  As strong as these bikes run, I'm sure many could be on their last leg and still "feel good".  The top engine rebuild with low overall mileage on the bike is good.  The places I ride and plan to use the bike, the loads planned, there will be no guesswork about the condition of the engine.  I have always done my own engine work, which should not surprise anyone, and the collaboration with L.A. Sleeve Company on the machine work was assurance that I have a fresh and very reliable machine!

 

As for your wonderful new acquisition, and you will be thrilled before this is done, the guideline I follow is the factory Honda "Power-Up Kit".  This is actually tuning the bike to the European and other market standards.  I did not pull my tuning specs out of thin air, instead doing my homework and even acquiring a non-North America shop manual copy to verify my findings.  The post above with the official carb jetting specs PDF is from the non-N.A. manual.

 

From this non-U.S. manual, we can glean that the basic engine is exactly the same throughout the world.  (I researched the compression, cam timing, ignition and other key features to confirm.)  The tune differs in various markets, though.  In fact, there is a different carburetor model used in Australia that has a radically smaller main jet (112#).  If the PE78D Australian carburetor has the same throat/bore opening and air flow as the PE78C (other export markets other than U.S./N.A), this Australian bike has been severely detuned.

 

For those curious, the U.S. replacement carburetor is a PE78A.  There were originally two non-California (XR650R A) part numbers and one for the California XR650R AC models, each a PE78A type Keihin carburetor.  Keep in mind, the U.S./N.A. XR650R was originally for off-highway only use, an enduro motorcycle without street use equipment.

 

This Australian market bike is actually geared for asphalt highways at 41/15 sprocket gearing and comes with a complement of lighting, directional signals, chain guard and mirrors, more like the XR650L although we can assume there are no other similarities with the air-cooled XR650L model.  I'm encouraging an Australian XR650R bike owner to jump in here to confirm that the Down Under XR650R is otherwise a true Honda XR650R.  For those curious, here are the model distinctions for Honda XR650R models sold in markets outside the U.S. or North America:

 

Attached File  Honda XR650R Markets.bmp   2.89MB   3 downloads Attached File  Honda Euro and Australian XR650R Models.bmp   1.65MB   4 downloads Attached File  Honda XR650R Carburetor Tuning.bmp   860.68KB   5 downloads

 

"Uncorked" is the parts list I've furnished in the above threads at this topic.  These part numbers have been available through Honda motorcycle dealerships and online official Honda parts suppliers.  The 175 main jet is standard for sea level on this engine everywhere in the world except North America and Australia.  The compression ratio of 10:1 justifies the 175 main jet for full performance.  That this 649cc engine will run on the 145 (aftermarket), 125 (N.A.) or even the 112 main jet at Australia, is a testimonial to the engine's stamina and flexibility.  A 125 or 112 main jet with a carburetor bore like this and 649cc engine displacement, sounds like a piston hole looking for a place to happen!

 

Like your bike, my engine had a half-baked approach.  The restrictors were removed from the air box as per Power-Up guidelines, and the OE manifold was round like your non-California engine.  (My bike sold originally in Texas.)  The needle-and-seat, the pilot jet and the muffler tip were Power-Up variety, too.  For the longest while, I could not imagine why the engine had every Power-Up Kit mod except the 175 main jet.  It finally dawned on me that the previous owner may have reinstalled the 125 jet when compression dropped and the engine seemed to run rich.  This was from the intake valve damage and loss of compression, not from over-fueling the engine with a 175 main jet at Texas.

 

Those familiar with my books and journalism know that I do not make assertions that fly in the face of OEM norms.  My jetting recommendations are Honda's own, both stone stock applications sold outside the U.S. and the "kit" that was allowable for these bikes as "off-highway" use only.  Off-highway or "competition" improvements do not violate EPA and California emissions because the bike is not presumed to be street ridden.  (There is a Green and Red sticker program in California, but we'll leave that issue alone.) 

 

Note: There's a jetting chart and comments at http://xr650r.us/jetting/.  What you'll discover is that the baseline for the author's chart is a 175 main jet at sea level.  He adjusts for both altitude and ambient temperature.  His main jet chart goes as high as 182 (sea level at 20 degrees F) and as low as 150 (for 12,000 feet elevation and 100-degrees F if you can find such a place on Earth!).  Nowhere does he mention a 148 or smaller main jet.  He talks about the HRC and Power-Up parts and also the Stage 1 camshaft that I'm running.  His chart includes needle settings for the B53E needle and seat package. There is also commentary about the standard pilot jets versus the "S" pilot jets. The author and I believe that reading spark plug coloration is a sensible backup to any jetting experiments.

 

So, what you need to do is compare your bike to mine, and that's not difficult.  At the magazine's free articles and how-to videos on the XR650R work, and clearly at the highly detailed 54-minute HD video how-to I did on rebuilding the top-engine (a streaming rental at Vimeo), you can readily follow the camcorder and photos as I show the intake manifold, the tailpipe and the unrestricted air box.  These parts are easy to spot and compare.  Whether you have the N.A. type tailpipe tip or the Power-Up Kit version will be clear.  There's considerable size difference in the tailpipe outlet. For a quick comparison, see my coverage of the TCI rack installation.  The muffler and tailpipe tip are prominent in the article's photos and the video.

 

Worth noting, I stayed with the stock air filter box, air filter and flame trap.  I tossed out the popular brand aftermarket air filter that could not seal properly at the edges.  (You hint of a similar issue, Greg.)  I'm now running the OEM Honda replacement parts, including a new flame trap screen, new OEM air filter and a new air box "O-ring" that seals between the black air box and the white side cover's lip.  I'm sure many have stories of performance gains and unleashing latent horsepower from aftermarket air filters.  I have no desire to periodically replace intake valves and service the cylinder.  Nikasil is very tough but can be seriously damaged by fine dirt running constantly through the upper cylinder.  Considering our alkaline dust at Nevada, I opted for the stock air filtration system.  The engine's performance is excellent, with no signs of air flow restrictions, and I'm good with "stock"!.

 

We're both very fortunate not to have the California suction valve system and other one-off pieces for the Golden State models.  If you have the wherewithal, consider doing a cylinder leakdown test for piece of mind. If you do so and the engine still has the auto-decompression OEM camshaft, make sure you back off the rocker adjusters enough to be certain all four valves are seated with the piston at TDC on the compression stroke.  Many try to run a conventional "compression test" on these engines, only to find that compression is a fraction of "normal".  An exhaust valve unseating as you kick through with the auto-decompression type camshaft will do just what de-compression is designed to do: release compression to ease cranking!

 

As I noted in a thread above, the Hot Cams Stage 1 camshaft is a sheer joy.  You and I can readily start a thumper with just the hand compression release lever.  (I describe my current kick starting technique, which differs some from the B44, but not in principle.)  Many seem to like Honda's auto-decompression, I cannot figure why.  On top of that, the camshaft's weight with the decompression mechanism is an awful lot of upper valvetrain mass to spin at speed.

 

Talking about speed, these engines when operated properly, which is to say by taking advantage of the massive low- to mid-range torque (more of both with the Stage 1 camshaft!), do not require redline throttling.  We understand this from having pushrod Beezers.  I had three of them, each '69s by coincidence, the B44, an A65L and an A75R Rocket III.  I actually liked the Lightning 650 twin on the road, it was far less weighty and more nimble than the A75R, although the A75R triple cylinder engine was significantly smoother and did tolerate extended high rpm operation.  Gene Romero (Triumph Trident) and Dick Mann (A75R BSA) proved this.

 

That said, do we plan to reenact "Dust to Glory"? (Watch this streaming from Netflix or rent the DVD, you'll see what an HRC version of the XR650R does for Johnny Campbell, Andy Grider, Steve Hengeveld, Mouse McCoy, the Roberts family team and others.)  Our rpm ceiling and riding may not create fuel starvation even with a 145 main jet.  An old tuner's trick, you likely know, is to run slightly rich, short of fouling the plug or fuel-washing the cylinder(s).  This keeps the upper cylinder cooler.  On the Honda XR650R, liquid cooling likely compensates some for the ultra lean mixtures in N.A. carburetors or even the Moose Racing kit.  Synthetic oil goes a long way here, too, and so does Nikasil.  A friend at Portland shares that just switching to Amsoil on his XR650R made his leg on the exhaust side of the bike substantially cooler.  I'd like to test and confirm this.  As you crack the throttle, you can instantly feel exhaust heat when the XR650R makes horsepower and BTUs!

 

What it comes down to is actual air-fuel ratio.  I am academic, and if I thought the 172 main jet was risky, I would install an oxy-sensor bung at the appropriate position on the muffler and test with an A/F meter.  More traditional testing, like spark plug color after hard acceleration and a quick shut-off, would be equally revealing. 

 

I can tell with my engine that the 172 main jet will work well at our altitude and with the Stage 1 camshaft.  If I encounter trouble above 6,500 feet, I might consider a change.  Short runs over Ebbetts or Carson Pass would likely not create an issue, I've done this with stock sea level and slightly leaner jetting on many of my motorcycles.  And planning for such a trip, I might simply install a hotter spark plug for climbing over the high passes.  I'll update on this point.

 

I look forward to our discussions, Greg, and hearing more about your bikes.  Happy to address our 2000 model XR650R motorcycles or the twin-carb XR air-cooled models.  Even happy to reminisce about BSA motorcycles...Thanks for joining us here, looking forward to starting new topics and threads!

 

Moses



#10 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 11 August 2014 - 03:16 PM

Hi Moses, I subscribed once I read your posts in this thread. I'm sorry to read about your misfortune with your xr650r. I just bought an 2000 XR650r a couple of days ago, I have no prior experience with them. I'm an old rider, I too used to ride a BSA B50 and have a 1982 XR500r and a 1984 XR350R. I've been trying to figure out if my bike has been "uncorked" as they call it. The prior owner knew nothing about any mods. The exhaust is not restricted. I pulled the main jet and it is a 145RD. The prior owner was satisfied with the performance, none of his friends could keep up with him. The rear sprocket was changed to lower the gearing for trails, so it probably was not ridden at WOT too much. That is what I'm hoping. Before I started the bike when I got it home I found the air filter leaking dust, so I have not ridden it yet. The rubber boot was still in the airbox but the plastic is not. While the filter is being shipped I have delved into the uncorking of my bike or lack thereof. Until I read your post I could not find anything definite about the stock jetting. The Moose kit has raised my brow as to the 145RD jet in mine. I just pulled the carb and there is no restriction in the manifold. This bike was sold new in Seattle. When my jets arrive I'll disassemble the carb and see what else is in there. Thanks for your informative post. I hope other xr650r owners will post what they found in their bikes before they "uncorked" their BRP.

 

Greg

Hi Greg,

 

I'm interested to learn of your progress with carb jetting on your bike. What altitude are you at, and what sorts of temperatures prevail when you ride?

 

As far as the rubber boot you mention - assuming you're not referring to the rubber o-ring that seals the air box to the side panel - if it's present, from my understanding, the bike is not fully uncorked. If you remove it, the bike will lean out further (more air in comparison to fuel) and the main jet will need to be bumped up "number-wise." Did you get a Moose kit? What is in it? I got one (EU spec, from a website in France, though I'm not sure that's any different from Moose's US version), but I don't have it where I am now, so I don't recall the specifics.

 

The bike that has fallen into my hands (2002 EU model) has the same problem as Moses's did - cylinder, piston and intake valve problems. It had been run without an air filter and with questionable carb condition and cooling system for an unknown period of time. I'm doing basically the same thing Moses did to rebuild it but without the cam. He's put a great video together, so I feel as if I know what I'm doing :). Luckily I'm on a trip to the US and I'll be here until the end of the month. Should be enough time to get all the right parts.

 

Next on the list is tires...

 

Good luck!

David



#11 fullchoke

fullchoke

    Advanced Member

  • Members
  • PipPipPip
  • 13 posts

Posted 12 August 2014 - 05:07 PM

Hi David,

I very recently purchased my XR650R. I have not installed anything on the bike. I've been trying to figure out what has been done to my bike by the prior 2 owners. I have ordered the proper jets for the carb and they should arrive Wednesday at the local dealer. The 145rd main jet that is in my XR may have come from the Moose kit, I only know from Moses that it is not a stock main jet. The elevation where I live is under 500' and where I will predominately ride in Western Oregon is around 1000'. We also ride in Eastern Oregon where the elevation runs between 3-5k. Temps very greatly between morning and afternoon and probably won't be a concern. They also vary considerably between the seasons. I plan to jet rich enough to cover my near sea level riding and only change if I encounter problems. I have ridden my 1982 XR500R in all these areas with not much noticeable change except starting when hot can take an extra few kicks at higher elevations. The odd thing that has happened more than once with my XR500R, is at high elevations in Eastern Oregon on a cold start is that it starts when I first push the kick starter trying to find TDC. The 82' XR only has a kick starter activated compression release. The slow lazy push can start the bike and has startled me more than once. I ride trails with my sons and seldom reach WOT so good low to mid range power with crisp throttle response is what I want. Like you I don't plan a cam change because I want smooth power throughout the RPM range and hotter cams tend to produce power in more of a sudden rush at a certain RPM. I wanted to ask Moses about how the Stage 1 cam preforms, but I don't know if he is familiar with a bike that has not been modified to compare. If my XR650R at some point needs a rebuild like his did, I probably would try out the same upgrade.

Please tell us a little about Burundi and what the riding is like in your country.

 

Thanks,

Greg 



#12 fullchoke

fullchoke

    Advanced Member

  • Members
  • PipPipPip
  • 13 posts

Posted 12 August 2014 - 06:53 PM

Hi Moses, 

I'm going to attach a picture of my exhaust screen. I should have shown the end, but it is empty and looks like yours from the rear. Please let me know how it compares to yours or one from HRC if you know.

It's frustrating having a new bike with all this potential and be waiting on parts, even if I can only ride it around my back yard for now.

Do you remember the handlebars on your BSA 441. I took them off my old B50MX and put them on my 82 xr500r. I don't think anyone makes bars for dirt bikes like these anymore. I'm not sure how I like them on the Honda yet, but I do like a narrow bar for tight trails or cross country, making my own trails in Eastern Oregon. One thing it does is keep my boys off my bike... they hate them.

The Stage one kit you put in your bike, was it from Honda or Hot Cams?

The Carb in my XR650R is a PE 78ABOA with the B enclosed in a square and a mark of some kind after the last A that is not a number or letter.

This bike supposedly had only 3 rear tires since new, but I take that talk with a grain of salt. I think it could have been used much more, but I got it for a good price. The down side is the seat height, I'm 5'8" and shrinking. I have read about lowering that seat height but in doing so it changes the geometry to the detriment of the bike so I don't plan on doing anything except possibly finding a softer seat. 

 

I bought my BSA new in 1974 and rode it into the 80's. My buddies all bought TT500's, after I got the BSA, but the BSA  lead the way most of the time with the guys I rode with. The TT500 came out right after I bought the BSA and I would have gotten one too, if I didn't already have the BSA. Other than that right side shifter, I loved that bike, limited suspension and all. Once I started riding again a couple years ago when I got the xr500r I couldn't believe how smooth the old 82XR was by comparison. Now when I get on the XR650 I think I'll find an additional improvement. I watched Dust to Glory last night for the 1st time. That is a great movie!

 

I bought my 1982 XR500, 1984 XR350 and a 1982 XR250r surplus from the State of Oregon as a lot.(My oldest son rides an 1986 XR200R we got separately). I never did know where they came from but I think they were all from the same place. The front ends of the 82's were bleached out from the sun and the seat from the 250 was sun rotted. The 250 was in the worst shape with missing teeth on the sprocket and a solid chain. I think it spent a lot of time on it's side. All three had their gas turned to tar. I don't know how long that takes, but I think it is a very long time. All bikes(I Believe) had their original tires but the 250's were sun rotted off the rims. All three bikes started after a carb cleaning and of course their tanks cleaned and new lines. I love Honda reliability.

 

Thanks, Greg

Attached Files



#13 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 13 August 2014 - 07:06 AM

Thanks for the insights, Greg! Our favorite places compass still bears strongly NW. I'm a U of O grad (W '80), and we lived a total of nine years at Eugene/Springfield and Oakridge, two stints, 1977-82 and 1990-94. I contributed the 'Drive Time' column to the Oregonian from 1993-97. Know both sides of the Cascade Range, can remember Bend when the population was only 10,000! Did Search and Rescue with the 4x4 club out of Oakridge, we dispatched to the coastal range and rivers, Willamette Pass and Waldo Lake.

We'll compare notes on our riding interests and venues. I have two good Oregon friends who ride on- and off-highway, one with an XR650R dual-sport conversion, he's based at Portland and works at Warn. The other friend from Oakridge days is now at Brownsville/Halsey and riding a WR250 Yamaha to work at Cascade Pulp—he's settled down since his Honda CR period at Oakridge!

I recall the handlebars for the Victor 441, they did have a good feel. That bike was an absolute blast and proved the point: You're always riding the "best" bike ever, because you need to be in the game on whatever's beneath the seat of your pants! The BSA thumpers felt great for that era. In the desert and scrambles, we didn't know any better. Brit bikes were racing the Baja! In hindsight, the minimal front fork travel was horrible, I can still hear the forks bottoming! Vertical rear coil-shock suspension, by today's standards, was also terrible. I get a kick out of "On Any Sunday", watching the four-stroke bikes tail dance across the desert, the riders bobbing up and down with the rear suspension...First breakthrough was cantilever shocks, then the mono-shocks and our Honda Pro-Link—such a monumental gain, thrusting the bike forward instead of straight up and down!

The seat height is high on the XR650R. I'm a 32" inseam, and it's a stretch. I'm back at the gym now, consistently after the magazine had me parked in front of the computer for longer than I'd like to acknowledge...I, too, discovered some height shrinkage. Stood 5' 11" at my peak, a recent check has me barely 5' 10". According to most, some of this is age, though denial has me thinking that by pushing away from the computer, working out more and riding the dirt bikes, I can stretch back to 5' 11"—if not, at least I'll be healthier and happier! Will update on the effort!

As for the exhaust and uncorking your XR650R, the Power-Up Kit difference is in the tailpipe tip. If yours looks like mine, you're fine. Not sure whether David's Euro model comes with the Honda Power-Up tip, I'd like his feedback.

Regarding my Hot Cams Stage 1 camshaft (not a Honda HRC camshaft, which is more like the Stage 2 Hot Cams), I went with the Stage 1 for two reasons: 1) When researching, and my concerns are exactly like yours, I discovered that the grind is actually for low end to mid-range performance gains, not mid- to top-end gains, and 2) as I noted, the auto-decompressor on the OEM camshaft did not thrill me. The Stage 1 camshaft eliminates the auto-decompressor system. (In the magazine illustrations and videos, you can see the parts differences.)

In a nutshell, I am thrilled with my engine's performance, very stable idle and immediate, massive torque from throttle tip-in to redline. I don't over-rev this engine and shift well below redline by instinct, there's absolutely no need to wring out this engine, it enjoys being upshifted and laying down torque in the next gear up. (A sixth gear would be nice, I do like the stock 14/48 sprocket arrangement for my multiple use riding but find myself, amusingly, often reaching for a sixth gear, conditioning from the earlier XR experience.) If you're okay with using the OEM manual decompressor lever for starting the bike, I highly recommend this camshaft if you want a change. Is it a "must" over stock, and should you go to lengths and change out the camshaft? Probably not—unless you develop the same disdain I did for the auto-decompressor setup.

Your XRs from the State of Oregon sound intriguing, what a find! The account of how little they needed to get going again does draw attention to Honda reliability. I have the '84 XR500R under a tarp (dry climate here at northern Nevada, fortunately!) and earmarked for restoration. It's completely intact and quite solid. Our youngest son bought the bike over the phone from a San Diego County owner several years ago. (This is the son who just bought the 2003 Honda XR400R with 134 original, documented odometer miles!) He rode the '84 XR500R about 20 minutes with blue smoke coming out the tailpipe and parked it.

I took the XR500R off his hands for what he paid for the machine, well worth it. This front and rear disc brake model is easily restorable, and as a seasoned professional motorcycle wrench, I would expect to rebuild any used 1984 motorcycle's engine. (Similarly, our fellow forum member Forman rebuilt his Kawasaki KLR engine.) For those of us who ride the desert, these XRs are great machines. Objectively, a vintage XR200R, XR250R or XR350R makes a bit better tight and twisty bike for single track trailing. For a desert playa or sagebrush 'Hare-and-Hound', however, either is the XR350R or XR500R is in its element. So is the XR600R, XR650R or any of the Honda CRF models.

Where do you ride at Eastern Oregon, Greg? Do you get to the coast, too?  Let's open up a topic at our single-track travel forum:  http://forums.4wdmec...-you-have-been/!  Would be great to add some photos and get David's moto view of Burundi, too!

Moses



#14 fullchoke

fullchoke

    Advanced Member

  • Members
  • PipPipPip
  • 13 posts

Posted 17 August 2014 - 07:02 PM

Hi Moses,  My parts order from the Honda dealer came in Friday. I found a picture online of the stock exhaust tip. The tip in my bike is different and by description I think it is the HRC tip. The main jet in my XR650R was 145rd, the slow jet was 65s, the needle was the same as in the power up kit and in the 3rd slot. I put in a new stock air filter, fired it up, and it runs very strong. I only ran it around a parking lot when I bought the bike so I can't compare very well, except to say the power feels awesome now.

 

I would recommend to anyone that has purchased an XR650R to check what they have in their carb, no matter what they were told by the seller. If for nothing else than piece of mind.

 

The only problem I have now is the seat is too hard. Are you living with yours?   

 

Greg



#15 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 18 August 2014 - 02:50 PM

So, what did you decide for the main jet?  If all seems well, check the plug after a hot, hard pull (without going to the ER burn ward from mishandling a scorching spark plug!).  You'll find that opening the throttle is something enjoyable on this bike, just don't wheelie the bike through the neighborhood!  On that note, power does go to the ground with the correct seating position, and opening the throttle does not have to result in a wheel stand despite the many YouTube examples of wheelies on XR650Rs.  If the throttle transitions feel strong and smooth, and the spark plug looks okay for coloration, go for it...If any have questions about spark plug coloration, I'd be pleased to respond.  Just open up a new topic, and we'll discuss it!

 

As for the stock XR650R seat, yes, it is hard, especially after an XR350R or XR500R seat from the day!  This is the newer, spare seat design, a weight and mass saving gesture, in addition to keeping the seat height as low as possible on this already tall chassis.  As for replacements, a number of aftermarket sources offer seats (Acerbis for one) that boast improved riding position and cushioning.  We've discussed leg length and inseam, and this can quickly get compromised by thicker seat padding.  Touch-and-go here!

 

Moses



#16 fullchoke

fullchoke

    Advanced Member

  • Members
  • PipPipPip
  • 13 posts

Posted 18 August 2014 - 08:19 PM

I put in the uncorking set that seems to be recommended everywhere. 175 main, 68s slow and the 3E needle. The needle was in there already, but I put in the new one and the holder anyway. I'm not a wheelie kind of guy, when I unload my bike at a riding area, it is common to see someone else making dust, noise, and throwing rocks in the parking area. That is not me.

 

I've got to do something about the seat. If it had seat foam like our XR350R's, I would be happy. I could sink into the seat and  lose a little seat height at the same time. Because the seat had to be thin Honda made it hard, so heavy riders wouldn't bottom out. I weigh about 150#  and a 2x4 provides about the same cushion. The 1 size fits all isn't working for me. My inseam is 30 to 31,  and it came into play last night. I was riding around my place and getting dark so I stopped to get off the bike and put it away.  I reached out my foot but it went in a depression in the grass that I didn't see and over we went. I've never done anything like that before, but this is the tallest bike I've ever rode and for me to reach the ground I must lean it over. When it is on the ground it is a BRP and a heavy one at that. My old BSA was 300# but the weight was low. I didn't have to lift it as far. The XR650R is much more top heavy. I've heard of 3 ways to lower the seat. Soft foam so you sit into the seat. Cut down the seat(still hard) Drill some holes in the foam so the seat can collapse. I heard there is a rear linkage kit too that can lower the seat but I don't want that.  I need to do something.

 

Greg 



#17 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 19 August 2014 - 08:00 AM

Greg...Very pleased that you followed the "Honda Power Up Kit" formula for jetting and the needle.  The OE restrictors are likely out of the air box, too, right?...You'll be happy near home with this jetting, and I'm getting away with nearly the same jetting at rides to 6,500 feet: 172 main with straight 68 pilot and the needle at #3 clip position.  Will test even higher altitudes this fall, I'm headed to High Rock Canyon and surroundings.  Will be filming from the bike, I'll share the link after our ride.

 

Like you, I've ridden a very long time without feeling compelled to do many wheel stands.  I got my first two-wheel "Scooter License" at age 14 in Nevada, that was 51 years ago.  The limit was 35 mph and 6-1/2 horsepower, which I quickly ignored, building an outlaw Cushman with 8-plus horsepower and a peak speed around 60 mph.  The XR650R power to the ground is tremendous, however, you'll have no problem keeping the front wheel on the ground, especially when hard desert riding.  You're used to the XR500R, just imagine that bike on steroids!

 

I thought your seat issue might have remedy at Acerbis.  Their X-Seat offerings for Honda do not include the XR650R.  I found a listing for a seat cover, and this could be more to your liking, anyway.  The cover might allow some room for additional padding, and a creative upholstery shop can perform magic.  Give these folks a call or drop them an Email to confirm whether the cover allows enough room for added padding:

 

  http://www.2wheelpar...sBjahoCV8Tw_wcB

 

A place to begin, you need to be comfortable in the saddle!

 

Moses



#18 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 07 September 2014 - 03:18 AM

Hi guys,

 

So I'm finally back in Burundi, and I managed to get all my parts here without TSA in New York messing about too much wondering what the heck a cylinder and piston were doing in my luggage.

 

I have opened up my carburetor and have found essentially that it's the same as a power-up with the exception of the pilot, which is a 65s. I decided to leave it in there, rather than replace with what came in the Moose kit (65 not s). I will contemplate ordering a 68s if I'm not happy with how things turn out. 

 

Aside from the 65 pilot, the Moose kit came with a 125 (yikes!) main jet, and a needle stamped D630. Their needle looks exactly the same as the B53e that's in my carb, but it's hard to tell. Since this is not a wear item, I left mine as-is. I was slightly disappointed not to find a new rubber seal for the carb top in the Moose kit. I guess my old one will have to do.

 

What I was happy about, is that there was a new fuel screw in the kit. Mine (as mentioned above) had been jammed in and the head mangled by some ham-fisted idiot (before this ham-fisted idiot got his hands on it :) ). As you suggested, Moses, small drill and an easy-out did the trick. Once out, I found that it had no washer or o-ring on it. I doubt that would have much impact, but at least now it's all set with a new screw, washer and o-ring.

 

As far as the main jet is concerned, I opted for a 170 in place of the existing 175. My reasoning after looking at the general web-wisdom is to compensate for the high-ish temps and 3,000 ft+ altitude where I'll be riding. I have a 172 to try if this seems too lean, but if it seems too rich, I'll have to order a 168 which I didn't buy when I had the chance....

 

Next task... Installing the new cylinder and piston!

 

By the way, there's a good how-to for the carb at http://www.xr650r.co...carb/carb.shtml. It can probably be found elsewhere as well.



#19 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 09 September 2014 - 08:26 PM

Hi, David...The 65s at your altitude could work very well.  I find the 68 (non-"s") works well for me, and I would run it down to sea level if riding there.  My needle preference is 3rd clip position from top of needle, and the 172 main jet works well for me. 

 

Your OEM is a 175, which confirms that Euro non-U.S./N.A. models use a 175 stock.  (Australian models are much leaner, another story altogether.)  A 170 or 172 will likely work well at your elevation.  I will comfortably use the 172 from sea level to at least a 7,000-feet ceiling.  Again, my primary riding is at 4000-5500 feet, and I do have the Stage 1 camshaft. 

 

Talked to a Baja 1000 racer last night at the BFG tire launch in Mexico.  (Just got back from the new All-Terrain KO2 light truck/Jeep tire testing, more on that later!)  He's run his XR650R on a 175 main and shares that this "sea level" tune is tolerable to 9,000 feet.  Given my current sense for the Keihin carburetor, I would be more conservative and stick with short rides at 6,500-7,000 feet elevation for the 170-172 main jet size.  I'll play with this in the future and comment further.  175 is fat and probably just "tolerable", not in any way optimal, at high altitudes.  This range of jetting may well reflect the forgiving nature of an XR650R engine.  Let's compare findings when you get your bike running.

 

Given that these engines have been tortured by factory 112 and 125 main jetting, with 145 bantered around as a "performance" jet in the aftermarket, 170 is certainly a place to start at Burundi for an uncorked (Honda Power-Up spec) or European spec engine.  (A North America OEM corked XR650R engine, and especially a California "AC" type, would be a whole different tune.)  With the uncorked style exhaust tip, round intake grommet/manifold, plus an air box with restrictors removed, you should be thrilled with the 170 main and 65s pilot.  Again, this carburetor and engine are not hypersensitive like a two-stroke, and buying a 168 jet seems unnecessary.

 

The washer and O-ring on your new pilot needle is practical and functional.  This prevents an air leak past the pilot jet threads.  An air leak will destabilize the air mixture and cause irregular idle and poor starting.  You'll now get an accurate setting, as the O-ring and washer will seal snugly.  Good!

 

I see that the main jet choice in the U.K. rebuild of the carburetor is a 172.  He's happy, I'm happy, you'll be happy with the 170.  On that note, you do have the same tailpipe tip as mine, right?  The same rubber intake manifold shown in the U.K. carburetor illustrations?  No air box restrictors, right?

 

In my experience so far, a 170-175 should work well for extensive riding at sea level.  You will not burn a hole in your new piston with a 170 at sea level, and some find that even a 165 will work okay in an uncorked engine.  Again, the main jet size addresses open throttle fuel flow volume.  Realistically, anything from 155-175 will likely produce a lot of horsepower at higher rpm.  I find, however, that 172 seems right for great roll-on throttle at any rpm with very smooth power flow.  It just feels right, and you'll have to ride your cycle to know whether the 170 is your optimal formula or not.  The 65s pilot jet should work just fine at your altitude.

 

Looking forward to the best outcome from your top end rebuild...Let us know how that's unfolding.  When you are ready to run the engine and test ride, the success of your carburetor tuning will be very clear. 

 

I may do a short video on how to start a Honda XR650R.  Way too much discussion online with exotic starting procedures.  I believe many riders are flooding their engines to death.  Not necessary!

 

Moses



#20 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 11 September 2014 - 01:02 AM

Hi Moses,

 

I have the same exhaust as you and Greg, but mine has a frying pan rattling around inside. Must have been an option for those who really want to rattle the windows. I will cut the muffler apart downstream of the collector and see what I find in there. I'm 99% sure that it's the tack welds of an internal pipe that have failed. The easy part is opening it up. Then I'll need to find someone who can weld (or braze?) it back together again.

 

And indeed, my bike has no restrictors or snorkel in the airbox (nor in the carb insulator).

 

D.



#21 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 11 September 2014 - 02:45 PM

David...I like your can rattle metaphor!  Had a special moment at Baja, Mexico this week.  We were inland 60 miles from Ensenada, middle of nowhere, storm clouds brewing, stopped for a driver change in our Ford Raptor pickups and racing buggies.  The setting would be homelike for Burundi, I'm sure, the humidity spiked up, thick clouds threatening rain, puddles dotting the dirt road, obviously from overnight cloudbursts.  Suddenly, I hear a familiar note, the staccato of Honda XR motorcycles.  Swarming into a group, just up the road, were a bunch of hardcore dirt motorcyclists.  They were tackling our route and obviously hitting the higher gears.

 

While we chatted about race vehicles and the new BFG All-Terrain KO2 tires, I watched 10 bikes launch down the road at 150 yard gaps, just enough to quell the dust.  Yep, the distinctive exhaust notes were nearly all Honda XR650Rs, there was a lone XR400R also clipping through the gears!  The exhaust notes rapped out, and you knew they were having a good time! 

 

Two engines will catch my ear: the Honda XR650R and a P51 Mustang's supercharged Rolls-Royce Merlin.  We now live near Reno and were at Yerington, Nevada for the 15 previous years.  The Reno Air Races (this weekend at the old Stead Air Base) feature P51s, and the pilots often test in the skies over our area.  I've been to the races and spent as much time in the pit area as the grandstands.  These modified V-12 engines are formidable, and the huge props have a distinct pitch in flight.  An approaching XR650R or P51 will spin me on my heels.  In still air, you can hear a P51 from miles away.

 

I have some welding how-to videos at the magazine site if you have the equipment.  The steel in the muffler should be easy to gas weld if you do not have a MIG or stick welder.  You'll have more control and uniform cool down with oxy-acetylene welding.  (Better not to braze here.)  If the inner parts are the same material as the outer canister, I'd use ER70-S2 filler rod, commonly available.  (A "coat hanger" weld would likely work at remote Baja!)  Make sure there are no gasoline fumes in the muffler before welding!

 

Type the word "oxy-acetylene" (without quotes) into the magazine's search box at www.4WDmechanix.com.  You'll return a list of links for my gas welding instructional.  Enjoy!

 

Moses



#22 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 15 September 2014 - 03:42 AM

Having now figured out how to post a photo (thanks Moses), here are the innards of my pipe. It sounded like a frying pan, but it was really the kitchen sink!  

 

 Attached File  20140912_175936.jpg   71.17KB   0 downloads

 

I've yet to check out the welding resources on the magazine site, but I will. Even though I won't be welding it back together myself, it'll give me a sense of knowledge for when i find someone who has the equipment and skills.

 

D.



#23 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 15 September 2014 - 05:59 AM

The gas welding (oxygen-acetylene) process is optimal for this fix, David.  The amount of oxidation rules out TIG, it would be near impossible to descale the parts sufficiently for that process.  MIG (GMAW) is an option, a talented stick (SMAW) weldor might be able to do the repair, too.  (Maybe a pipeline trained Burundi welding expert?)  Thinner gauge, older metal like this, I really like oxy-acetylene.  Check out the magazine video examples, you'll understand my enthusiasm for gas welding in these cases.

 

When you have the piece repaired, make certain the weldor positions the two shell parts as they were originally.  Given the bends and twists in the muffler assembly, off-setting even slightly would have dire consequences when trying to reinstall the muffler! 

 

Should turn out well, this is resourceful and saves considerable cost.  There are several aftermarket mufflers for performance gains (FMF and others).  You've likely racked up enough startup costs for now!

 

Moses



#24 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 17 September 2014 - 12:18 PM

Did the pipe yesterday. Quite an artisanal butchery, but I guess it's about as good as I can expect in this neck of the woods.



#25 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 17 September 2014 - 01:52 PM

Moses, you will note that indeed, a gas welding solution was found. It might not have been done in the "clean room" environment you would prefer, but I guess it'll have to do the trick. 

 

What I did was to go around the "technical" neighborhood asking welders if they could show me samples of their work. Having established that this guy actually had the necessary tools (rudimentary as they were), I settled on what would be considered locally as an exorbitant price (about $20) and he set to work re-assembling my muffler.

 

The end result is not super beautiful and I'm tempted to take a grinder to some of the rough spots, but it's good enough. The worst of it is hidden by the side cover. In the end, a grinder might be counter-productive as the weld material looks extremely porous and any diminishing of the material volume might lead to leaks. I painted it with barbecue paint (800 F test - best I could get), and tomorrow it will be put to the test. Not sure if it's gonna hold up under the temps generated by this bike, but we'll see. Maybe I can try to "bake" it on in stages during the break-in.

 

Back to the tools and materials side of things - you will note the "milk can" in the photos. This is the acetylene supply. What they do is to toss a lump of "carbonite" (which is essentially charcoal from Eastern Congo) into this vat. The only other thing in the vat is water. However, it somehow magically produces the acetylene. They took it seriously enough to set this vat away from any open flames!

 

Fun!

 

D.

Attached Files



#26 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 17 September 2014 - 04:50 PM

Fascinating, David, the photos say it all!  I haven't seen innovative welding like this since watching the BMW frame repair at Mongolia during the 'Long Way Round' movie with Ewan McGregor and Charley Boorman.  Hey, ya gotta do what ya gotta do!  (A great song, incidentally, recently resurrected in the movie "Blood Ties".  I knew the Johnny Rivers version from my high school days, the soundtrack in the movie was Al Wilson's take.)

 

The key to success with welding is the complete fusion of metal that underlies any weld.  What you want here is enough heat to melt the base metal on each side of the weld, then the insertion of a metallurgically appropriate filler metal into the molten puddle. 

 

This technology may not warrant discussion with these weldors at Burundi.  However, I never underestimate the capacity or skill of any practiced weldor.  Fortunately, welding is as much a hand/eye and intuitive application as it is academic and technical.  When I taught welding, we had a particular student who did well with oxy-acetylene and went directly to TIG, laying down exceptional GTAW welds.  Upon graduation, he wound up performing aircraft engine impeller repairs.  His training was no different than others, and some students, frankly, failed to master the craft, never grasping how much heat to apply or when to dip the filler metal into a liquid puddle.

 

When I watch weldors, I'm absorbed in their "process" and immediately conscious of right moves and wrong.  This is from practice that began with a year of welding training in high school.  I was fortunate enough to experience the post-WWII methodology:  start with basics and get as much hands-on time as possible.  Our instructor, who doubled as the FFA (Future Farmers of America) chapter advisor, repeatedly drove home the fundamentals.  As a result, we each learned to gas weld, braze and stick weld properly.  I thank Mr. Gray, he paved the way for my later training and many years of professional welding around engineering plant repairs, heavy equipment repair work and automotive technology.  When I can muster the time, I'd like to produce a series of welding instructional HD videos and impart that experience.

 

Best not to grind off any metal...I'll keep my eye open for a pristine stock muffler, David.  Often, owners discard the OEM system when upgrading to performance equipment...Maybe we can drum up a backup unit.

 

Moses



#27 DavidEasum

DavidEasum

    Advanced Member

  • Members
  • PipPipPip
  • 50 posts
  • LocationBurundi

Posted 18 September 2014 - 02:00 PM

Hi Moses,

 

I guess indeed, I gotta do what I gotta do. I went to check out both versions. Even though I grew up (at least part of the time) with AM radio, the Johnny Rivers version didn't ring a bell. The Al Wilson cover however made me think of Tom Jones. I hope I'm not cheapening your memories!  B)

 

Not to change the subject; but the sound of my locally rewelded stock pipe with "Euro" tip, is a sweet and crisp song. Unfortunately it hasn't lasted. More detail on the engine rebuild thread.

 

D.



#28 Moses Ludel

Moses Ludel

    Administrator

  • Administrators
  • 1,177 posts
  • LocationReno Area...Nevada
Garage View Garage

Posted 18 September 2014 - 05:06 PM

David...So, we get Netflix and watched "Blood Ties".  The soundtrack was right out of my high school era, I graduated in 1967.  Johnny Rivers was popular, we lived at a rural ranching community.  A handful of my school chums were into British rock.  Johnny Rivers, Roy Orbison and other country/rock singers worked better in the local Nevada cowboy bars...I got into everything Motown shortly after high school but always enjoyed Johnny Rivers.

 

When we watched to movie, I was jerked back in time and went on a short refresher tour at YouTube around "Do What You Gotta Do".  After Johnny Rivers, there was Al Wilson, Tom Jones and down the list.  This was one of Jimmy Webb's greatest hits, he fueled the successes of Glenn Campbell and many others, including Johnny Rivers, obviously.

 

Here's what I found if anyone is curious:

 

"Do What You Gotta Do"

Classic Jim Webb sung by Johnny Rivers…

 

 

Here’s a year later (1968) and Al Wilson pressing the same song on a 45-rpm disk at the UK.  Note that Johnny Rivers is shown as the “Produced by” on the label…This is the true “soul” spin, a very clear and clean vocal rendition:

 

 

 

I actually like this Al Wilson cut better, there’s also a “Comment” below by someone who heard this song in “Blood Ties” and got a rekindle like I did:

 

https://www.youtube.com/watch?v=hi02YH039tg

 

Tom Jones couldn’t leave it alone and does a very decent rendition, especially as a live performer, getting "Tom Jones theatrical" at the very end.  You can see how much traction the song had at the time, this is still the late ‘60s:

 

https://www.youtube.com/watch?v=hMCjdnC40nI

 

This version goes far afield by Roberta Flack, a soulful rendition that relies totally on the lyrics, a major departure from the original rhythm and melody:

 

https://www.youtube.com/watch?v=UFIZXCoOIm0

 

Also from Roberta Flack, who had a vocal gift, this significant breakout song became best noted for its role in the soundtrack for “Play Misty for Me”, a movie starring Clint Eastwood that was a sensation in 1971:

 

https://www.youtube.com/watch?v=Id_UYLPSn6U

 

Nina Simone does it, too:

 

https://www.youtube.com/watch?v=2jQC6L5Z108&list=PL79EA484ED19DD8CD

 

This is the Four Tops version, which is very well done, too.  Motown overtones for sure.  Lead singer Levi Stubbs nails it, he's Jackie Wilson's cousin, each had a great voice:

 

https://www.youtube.com/watch?v=U0svbAv8bDQ

 

If this resonates, enjoy the flashback.  That era spurred my purchase of the three BSA motorcycles in the early '70s.  Unlike Bob Dylan's short interest in a Triumph (long enough to make an album cover at least), I never fell off my Beezers!

 

Moses





Also tagged with one or more of these keywords: dirt motorcycle, off-road motorcycle, dirt bike discussion, dirt bike how-to, dirt bike troubleshooting, thumper motorcycle, Honda XR, motorcycle backcountry riding

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users