Jump to content

Search the Community

Showing results for tags 'dirt bike troubleshooting'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Jeep® 4WD Owners Group
    • Vintage Jeep® Vehicles 1941-71
    • 1972-86 AMC/Jeep® CJ and Jeepster Models
    • Jeep® YJ Wrangler, TJ Wrangler and LJ Wrangler
    • 2007-Up Jeep® JK Wrangler 4x4
    • Jeep® XJ Cherokee, MJ Comanche Pickup and Grand Cherokee
    • FSJ Models: Full-Size Jeep® Gladiator and J-Truck, Cherokee, Wagoneer and Grand Wagoneer
    • Jeep® Liberty, Commander and Patriot
  • Dodge Power Wagon, Dodge and Ram 4WD Trucks
    • Dodge 4x4 and Ram 4WD Trucks
    • Dodge-Ram Cummins Power
    • 1941-1980: Dodge Military Trucks and Civilian W-Series Power Wagon
  • Chevrolet & GMC 4x4 Trucks and SUVs
    • Vintage to 1991: Chevrolet & GMC NAPCO and K-Model 4x4 Trucks
    • 1987-Present: Chevrolet & GMC Silverado, S-Trucks and 4x4 Suburban, Yukon and Blazer
    • Humvee and Hummer H1, H2 and H3 Forum
  • Ford 4x4 F-Series, Full-Size SUV and Ranger Trucks, Bronco II and Explorer
    • 1948-Present: Ford F-Series Trucks
    • Full-Size Ford SUV, Bronco 4x4, Excursion and Expedition
    • Ford Power Stroke Diesels
    • Ford Ranger, Bronco II, Explorer and Mercury Mountaineer
  • International-Harvester 4x4 Light Trucks, Scout and Scout II
    • International-Harvester 4x4 Light Trucks, Scout and Scout II Forum
  • Toyota Truck, Land Cruiser, FJ Cruiser, Toyota SUV and Lexus 4WD
    • Land Cruiser 4WD FJ, DJ and FJ Cruiser
    • Toyota Sequoia, Lexus, Highlander and Rav4
    • Toyota 4WD Pickup, Hi-Lux, Tacoma, Tundra and 4Runner
  • Datsun and Nissan 4x4 Trucks, Pathfinder and Xterra
    • Nissan Patrol, Pathfinder, Xterra and SUV 4x4s
    • Nissan 4WD Pickups: Datsun, Nissan, Frontier and Titan
  • 4WD Land Rover Community
    • Land Rover, Discovery & Defender 4x4s
  • 4x4 Suzuki Samurai and Sidekick/Geo Tracker
    • Suzuki 4x4 Samurai
    • Suzuki Sidekick and Geo Tracker
  • Isuzu 4x4 Pickups and SUVs
    • Isuzu 4x4 Pickups and SUVs
  • Travel Trailers, Toy Haulers, Tent Trailers and Military Surplus Trailers
    • Travel Trailer and Toy Hauler Forum
    • Military Surplus M415, M416 and Other Off-Road Trailers
    • Tent Trailers and Trailering
  • 4x4 and Single-Track Travel & Adventure Destinations!
    • Places You Have Been...
    • Places You Would Like to Travel!
    • Off-Pavement Travel Gear
    • Equipping Your 4x4 for Overland Travel
    • Health and Fitness for Four-Wheelers and Powersports Enthusiasts
  • Dirt & Dual-Sport Motorcycles
    • Dirt & Dual-Sport Motorcycles
    • Dual-Sport and Dirt Motorcycle Equipment for Overlanding
  • Quad ATV, UTV and Side-by-Side 4x4s
    • 'Quad' ATV, UTV and Side-by-Side 4x4s!
  • Welding, Metal Fabrication and Metallurgy Discussion
    • Welding and Metal Fabrication Forum
    • Metallurgy and Heat Treating Forum
  • The Right Tools and Equipment
    • Garage Tools and Equipment
    • Diagnostic and Specialty Tools & Equipment
    • Tool and Equipment Sources
  • Let's Talk and Share!
    • General Repairs and Tips (See Other Forums for Specific Vehicle Topics)
    • Off-Topic and General Discussion
    • Sharing New Products
    • Calendar Events and Outdoor Activities
  • Parts for Sale, Swap or Wanted
    • Parts for Vintage (1941-71) Jeep Vehicles
    • Parts for AMC/Jeep CJ, FSJ Cherokee, Grand Wagoneer and XJ Cherokee/Comanche
    • Parts for 1987-up Wrangler Models, Grand Cherokee and Liberty
    • Parts for 4x4 Dodge and Ram Trucks
    • Chevrolet & GMC Truck Parts
    • Parts for I-H Trucks and Scout/Scout II
    • Parts for Toyota, Nissan and Other Import 4x4 Trucks and SUV Models
    • Parts for Motorcycles, ATVs, UTVs and Snowmobiles
  • Equipment and Tools Classified Ads
    • Hand and Power Tools for Sale
    • Garage and DIY Equipment for Sale
    • Tools and Equipment Wanted

Blogs

  • 2018: "Year of Speaking Out!"

Product Groups

There are no results to display.


Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Location


Interests

Found 10 results

  1. 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!) 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! 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. Hi Moses, I have a question about the dual-sport lighting conversion that was done on your Honda XR650R. I'm wondering what type of flasher relay was used for the turn signals. I'm trying to (re)install the turn signals on mine and, being ignorant about things electric, I am concerned that a bike with no battery may need a flasher that is different from bikes (or cars) that have batteries. The original flasher (OEM for this world-market ED/DK model) was cut out of the harness and thrown away at some point (can't figure out why though...). I went out today to find a replacement - thinking that any 12V moto flasher would do - but was only able to find 2-wire flashers, while the Honda harness provides for 3 wires. Furthermore, I was not able to find any flashers for bikes that don't have batteries. I'll look at car flashers next, but obviously none of those will have a non-battery electric system. Even if I had a source for Honda parts here, I'm not sure if the OEM flasher is available anymore - I went on the site selling international market Honda parts, and while the flasher is shown in the diagram, it is not in the price list. Are my concerns unfounded? Is a flasher just a flasher - and I only need to find one with the right amount of terminals? I know that some are designed to be impacted by the voltage draw (depending on the bulbs used), so I may end up with a fast or a slow flash, but it'd be great to at least have some kind of signal working for when I ride on the street. I can tune the flash later by changing bulbs (assuming I can find variants). Feedback welcome! David
  3. Many of today's dirt motorcycles have electric starting, and this is a very good idea for the contemporary ultra-high compression four-stroke singles! For these operators, unless the starter fails to work, manual kicking has become a thing of the past... Despite this trend, there are still many kick-start Honda four-stroke motorcycle engines that have an "auto-decompressor" start mechanism. This device, typically mounted at one end of the overhead camshaft, unseats an exhaust valves during crankshaft rotation. The aim is to relieve compression as the piston approaches TDC (top dead center) on the compression stroke, only during kick start phase. Once the engine starts, the mechanism disengages the ramp/cam that opens the exhaust valve during kick starting. On my Honda XR650R engine, the OEM camshaft was still in place when I purchased the bike. The engine did not run, and repeated attempts to kick it over proved futile. Eventually, I ran a leak down test and discovered a considerable loss of compression caused by leaking intake valves. Despite this low compression, the kick starter repeatedly balked as if the auto-decompressor was stuck off. Even with leaking intake and exhaust valves, the engine would not kick over easily. The auto-decompressor was stuck in the off-position and acting as if not even there! Large piston displacement gave a false sense of "compression". The bike had set for some time, and perhaps this accounted for the condition of the auto-decompressor. It felt like the mechanism was sticking in the released position, providing no decompression. Even with the low compression from leaking valves, I found myself using the hand lever decompressor to "free" up the compression resistance and what felt like a jammed kick starter. Note: Wondering why an engine with leaking intake valves would still be hard to kick over? This is not hard to explain with the volume of air that this huge piston can displace, an overwhelmingly large amount compared to the amount leaking off from valve face-to-seat seepage. Given the kick start resistance, I never suspected worn, leaking valves. In fact, all four valves had a fair degree of seepage. By the time I committed to the leak down test that led to the upper engine rebuild, I had researched the XR650R engine. I'd also had enough experience (i.e., cardio workout) with the auto-decompressor to seek an aftermarket replacement camshaft without the auto-decompressor. I was not opposed to using a manual decompressor lever and knew from my first experience with a BSA 441 Victor how to find that special point, just past TDC on the compression stroke, where the engine kicks through without kicking back. Part of my rebuild was the choice to install a Hot Cams Stage 1 camshaft. This is a milder performance approach that provides more bottom end and midrange power—and a camshaft that eliminates auto-decompression. I'm good with my decision to eliminate auto-decompression and am curious how others have made peace with the factory start mechanism. Am I the only one whose auto-decompressor has stuck or jammed? I could have rebuilt and polished the OEM auto-decompressor, as the mechanism can be rebuilt. I opted out. Is everyone else happy with the stock camshaft and auto-decompressor? Please share your experiences here...An auto-decompressor is not unique to the Honda XR650R, they come in many forms and configurations, like the kick-start mechanism on my '84 XR350R, still a valve unseating approach, that has worked flawlessly and easily for three decades. From the XR600R forward, the auto-decompressor attaches to the camshaft and has a one-way clutch mechanism. How does that work for others? Moses
  4. Dear Mr. Moses Ludel! First of all, thank you for making these awesome videos, I really liked them! In the one, where you one-kick start the xr, if only there would have been some explanation too, I hear lots of people are strugling with that. Yesterday I subscribed to some of you videos on vimeo, because I would like to learn to be my own mechanic. I am about to buy a Honda xr650r bike on this monday, for this I am traveling 1300 kilometers to Italy and back home. I wish if only I have found your videos on Vimeo and these forums earlier! I am very excited about the trip. I do not want to bore (all of) you with personal details, it is enough that I fell in love with this bike and I cant wait to have my own. I have very little knowledge about what should I pay attention to, when selecting the bike, so because of this, I kindly ask your guidance. There are two brp models that I am going to choose from. One of them (Bike A) costs 2500, the other (Bike costs 3400 euros. Bike A is close to factory state - as far as I can tell - with 11000 km only. Bike B is around 25000 km but spoiled with lots of supermoto extras. No blue smoke, no cylinder jingle that I noticed by neither of them. (I asked the sellers to send me high res pictures and video with the engine running.)e Because at first I am planning to use the bike as a supermoto, I consider the two of them equals, because I will buy the extras either way. Both of them are street legal, and documents are fine. However I prefer Bike A, I would like the adventure of building my own supermoto. Either I use it at first as an SM or as an enduro, I am sure I will learn to ride a bike really well. (I only had naked and speed bikes earlier.) So may I ask your advice, Please, what should I really pay attention to when checking them? What noise or rusty-ness should I give special attention, and basically how should I compare the bikes of totally different cost ranges? Tomorrow, I have an opportunity to take a peek on two other xr650r in my home country, so the ones I will see in Italy should not be the first time I ever see a BRP in life Blind love, it is what it is Thank you very much! Kind regards, Sandor
  5. So, I have this Euro model XR650R project, and I acquired the bike right. As the upper engine rebuild and other restorative measures unfold, I'm starting to wonder what is a reasonable amount to invest here? The engine work and all the other parts I've bought are pushing things pretty close to $2k - and this bike can't be worth much more than that! Furthermore, I dropped nearly as much on new gear (helmet, boots, gloves, etc...) DON'T TELL MY WIFE! Cheers, David
  6. At the forums Garage Photo Gallery, member "FullChoke" (Greg) responded to my photo of the magazine's 1984 Honda XR350R motorcycle. We have identical '84 XR350R motorcycles. Greg's cycle has engine heat-up problems, and this raises the issue of how to keep any air-cooled dirt or dual-sport motorcycle engine running cool enough. I'll begin with sharing our exchange at the Garage (below), followed by pointers on how to keep an air-cooled dirt or dual-sport engine from overheating. ************************************************** My comments at the Garage Photo Gallery: Moses Ludel 23 September 2013 - 02:33 PM The Honda XR350R cycle has been in our stable since the late '90s. Rick Sorensen, an A&E aircraft professional, had set up this dirt motorcycle for desert enduro riding. Rick's attention to detail, tuning and appropriate upgrades has made this one of our favorite dirt motorcycles to date. When new, the 1984 XR350R came with many advanced features, including Pro-Link rear suspension, a disc front brake and the four-valve, twin-intake and exhaust thumper engine design. The performance, dependability and flexibility of this engine has been a constant source of satisfaction. Under the most challenging conditions, including crawls through milder "rock gardens", the cycle and four-valve engine have delivered tractor-like stability. In other online forums, there is much talk about the "failure prone" and "problematic" dual carburetors on the XR350R and XR500R engines. In my experience, nothing could be further from the truth. I have rebuilt these carburetors and set them up to factory specifications, adjusting linkage and cables accordingly. The dual 26mm Keihin carburetors are stable and flexible enough to get by with the same jetting from Johnson Valley (King of the Hammers) to timberline at Nevada's high mountain ranges. Note: I jet for our base at 4500 feet elevation. The carburetors tolerate short rides to 8,000 feet and drops to 2,500 feet. That's very flexible, and though I would re-jet for extended riding at either of these high or low altitude points, these carburetors will "function" over that range. Simply put, I'm not fiddling constantly with the carburetors. The transition to the secondary carburetor is seamless, and by making sure there are no vacuum leaks, the tuning stays rock steady. Sure, EFI delivers more power and refined tuning, but these twin Keihin 26mm carburetors do work well and can be adjusted, or even re-jetted with care and patience, when you're 120 miles from a paved road. As for handling, I always ride the motorcycle that's under me. Sure, a CRF450 or XR650R could "run circles" around these earlier XRs, but that's not what I'm riding here. The XR350R can provide a great ride when handled like, not surprisingly, a tuned XR350R and not a CRF450. This logic applies to road cycles, too. I never rode our Honda Gold Wing or the BMW K1100LT like I did my two 1969 BSA motorcycles, the lightweight 650 Lightning or the 750 Rocket III. When I hopped on my youngest son's Yamaha YZF600R6 a few years ago, that was a different story as well. For this XR350R workhorse, I'm considering a dual-sport conversion kit from Baja Designs to enable highway access. We have an '84 XR500R waiting in the wings for restoration, another dual-sport candidate. Each of these bikes would weigh under 300 pounds converted, much nimbler on dirt than a KLR or BMW in any form. Nevada's new OHV permit program makes it just as sensible to opt for a DOT-standards conversion and license ("plate") an XR for dual-sport use. We carry insurance either way. On that note, expect details shortly on what direction this takes. If the dual-sport conversion route, I'll cover the steps at the magazine in an HD video 'how-to'. Moses Greg's comments at the Garage Photo Gallery: fullchoke Yesterday, 09:22 PM The1984 xr350r has a history of running hot and burning up. I think that was blamed on the new head design and the 2 carb system. Possibly the overheating could benefit with richer jetting. I know mine gets hotter faster than any bike I've owned. I haven't run it much and when it is used it has been a buddy's bike, usually run fairly slow. When compared to other bikes running over the same terrain it is noticeably hotter. For that reason I run a full synthetic oil, hoping for more protection with a higher boiling point. The front disc brake is a very nice feature, best thing about a very good bike. Greg ******************************************************************* How-to troubleshoot an air-cooled motorcycle engine overheating problem: As for overheating, let's start with a systematic troubleshoot. First and obviously, the engine cooling fins must be clean with sufficient air flow. Also, a four-stroke engine does not like to idle for extended periods in still air. This even applies to liquid cooled dirt and dual-sport motorcycle engines. (There are constant internet discussions about overheat, even on models like the liquid cooled XR650R and others.) Two-strokes with premix fuel have less tendency to overheat, though heat can still be an issue. When we ride extensively in the desert during hotter weather, I'm always conscious of air flow. After a good high speed streak or even picking through basaltic rock flows, my Honda XR350R remains "reasonably" cool. I'll let the engine idle for just a moment to help stabilize temperatures before shutting it off. We do crawl in stand-up-on-the-pegs type challenges, one location in particular is at high altitude. This engine has never reached critical temperatures. Your use of synthetic oil can help, too. Running cool at high altitudes is in part what you suggest. Proper jetting for sea level to 4,500 feet, then running the engine at 7,000 feet, makes the fuel mixture richer. I've never fouled a spark plug or experienced blubbering or unstable operation with these richer mixtures. In my experience, jetting is not that sensitive on these four-strokes, they are way more flexible than many give credit. Main jetted for best performance at 2,500-5,000 feet (our typical high desert country), this same engine has run flawlessly from 2,300 feet on the floor at Johnson Valley, CA to nearly 7,000 feet—without a re-jet. Of course, if the engine were operated consistently at 6,000 feet or higher, I would re-jet. Keep the jetting within a reasonable range. Read the spark plug color after a hard, open throttle run and prompt shutdown! That's the main jet's realm. If anything, jet slightly rich. In current jetting, my XR350R can run at sea level without burning a hole in the piston. Again, if I were to run the length of Baja, I would jet for sea level to 4,000 feet. Never jet so rich that fuel can wash oil off the cylinder walls nor so lean that the valves and piston are at risk! Learn to read the spark plug. Often overlooked is the importance of proper valve clearance. Valves adjusted too tight will cause engine overheating and also lower compression. Unseated valves lead to valve face burnout and seat damage, too. Adjust valves to specification, and also adjust the decompression lever and kick start cables. This is a big part of maintenance on the XR350R, the XR500R and similar Honda dirt bike models. The auto-decompression camshaft design eliminates the kick starter cable on later XRs. However, the manual (handlebar) decompression lever adjustment remains very important on every one of these models. On the XR models with dual carburetors, folks need to get over the idea that these engines never run right. Actually, this myth is helpful to those of us who value the dual-carburetor era, Pro-Link models—you can buy them at bargain prices! A common mistake is for the carburetors to be sync'd improperly. There is a very clear adjustment here, which I can share if necessary. Be aware that these carburetors do not open simultaneously! The linkage is actually "progressive", with a lag stage as the primary carburetor provides a smooth idle and light tip-in air/fuel flow. Then the secondary carburetor (which has no idle mix screw) comes into play. Think of this like an automotive engine with a progressive four-barrel carburetor or multiple carburetors. Adjust the cables and the staged throttle linkage to specification. These engines will start readily and run fantastically if the jetting, float level and needle settings are correct! General footnote: Current ethanol fuel wreaks havoc on motorcycle carburetor passageways. Do not leave the bike parked for long periods with fuel in the carburetor bowls. Shut the petcock, and with the bike upright, burn fuel until the engine stalls. Fuel standing in the bowl will clog jets, it did mine. The immediate symptom is an unstable idle and poor low throttle response. (I ended up rebuilding both carburetors after letting the cycle sit for too long with "winterized" and "Ethanol" mix fuel in the tank and bowls!) Use a fuel stabilizer additive, this can help for shorter storage. Long term, drain the fuel tank and the carburetor(s). Without stabilizer, fuel can become stale and worthless in months, depending upon the climate. Air/fuel flow and ratio are a critical part of air-cooled engine performance. Keep the air filter clean and oiled properly, whether stock type or aftermarket. A clogged cleaner element will make the engine run rich or stall, much like leaving the choke on. Also, when considering a lean fuel mixture, always take air leaks into account. Air leaks on the manifold side of the carburetor(s), between the head and carburetors, can lean out the fuel mixture. Check for leaks at flanges and junctions. Using a can of spray carburetor cleaner or WD-40, spray a fine mist at flanges with the engine idling. This can quickly turn up an air leak as the engine speed flares up or changes. Avoid spraying at high heat areas that can ignite the spray! Once you've worked through the intake side, make sure there are no exhaust restrictions. I have a "tunable" SuperTrapp exhaust end that is set up with the right number of discs for proper backpressure. I periodically remove the disks and gently bead blast the carbon away to keep tuning accurate. Improper exhaust backpressure or clogging can be a major source of overheat on a motorcycle engine. After fuel mixture/jetting, carburetor sync'ing, air leaks and exhaust restrictions and tune, there is the ignition spark and timing. Of course, spark must be adequate, and the spark plug should be the correct heat range, especially on an air-cooled engine. A "hotter" plug can be serious trouble if not in place for a good reason. Hotter spark than the stock Honda ignition (in good condition) is rarely necessary. Note: The compression ratio is higher, so you also need to run better octane fuel, especially at lower elevations. This may not be true for high altitude. I can run 87-octane in the XR350R at 4,000-8,000 feet because the atmosphere effectively lowers the compression ratio. I am not as flexible with the Honda XR650R at 10:1 compression and a bore size within 0.060" of a 327 or 350 cubic inch Chevy V-8! If you're at a lower elevation with high compression, spring for 91-92 octane fuel. This helps prevent detonation/ping, overheat and stress to the engine. For an XR500R, XR600R or XR650R, I would run 91-92 octane all the time. The last item on our checklist is spark timing. Either retarded or over-advanced, spark timing error can kill a motorcycle engine. Check the spark timing from idle to full-advance at speed. Make sure the timing advance is set properly. You can test with a conventional timing light or a light with built-in advance, this is not rocket science. I can help cast light on the procedure and expected results. With an electronic ignition, spark timing either works or it does not. If a motorcycle is old enough to have a mechanical spark advance mechanism, like our BSAs of yore, a sticking or defective spark advance mechanism can cause overheating as well as performance problems. Of course, there are overheat causes unrelated to the engine, like too much friction in the gear train or binding brakes (a sticky front or rear brake caliper, brake shoes dragging or warped/defective rotors and drums). Wheel bearing resistance, low tire pressure or chain drag can also overheat an engine. Check for resistance with the motorcycle wheels and tires lifted safely off the ground or floor. This is a place to start, and I am happy to continue this discussion. Glad that FullChoke triggered this topic, that's what these forums are all about! Moses
  7. I pulled the oil filter and passed a large magnet over it but I did not pick up any ferrous metal. The close up photo of the filter reveals many small chips of aluminum. Well all I have to do is open up the motor and start looking for a bright shiny spot! This is the filter out of the 2006 salvage bike.
  8. I bought this 2002 KLR engine from a listing in craigslist for $100. The previous owner stripped out the oil drain plug threads then attempted to use a tapered bolt that spread the stripped threads and cracked the engine case. I have another set of engine halves. I could transfer parts from this damaged engine into the good case halves, but I was wondering if this case could be repaired as it sits? I'm pretty sure that the case is made of cast aluminum.
  9. Demand for more off-pavement motorcycle coverage has led to the launch of 'The Off-Road Motorcycle Channel' at the 4WD Mechanix Magazine's HD Video Network! The new channel covers dirt, off-road and dual-sport motorcycles, including tech how-to, step-by-step tuning and repairs, troubleshooting, backcountry riding and survival tips—everything related to off-road and dual purpose/dual-sport motorcycling! Inspired by the needs of the magazine's 2000 Honda XR650R motorcycle, the channel launched with HD video tech how-to coverage in Vimeo Pro 1080P full-screen detail. Whether you own an iconic XR650R Honda big-bore XR thumper motorcycle or a similar four-stroke, overhead camshaft motorcycle, you'll find the launch coverage of interest. The Honda XR650R cylinder head inspection after tear down. See the full HD video coverage. Check out 'The Off-Road Motorcycle Channel' playlist at: http://www.4wdmechanix.com/The-Off-Road-Motorcycle-Channel.html! Moses
  10. There's never been a time when someone else performed my motorcycle service work...Having always purchased "pre-owned" bikes, more than a dozen of them over the last half-century, there's never been a warranty requirement for taking a cycle "back to the dealer"... Of course, I strongly support OEM tech training and service work performed to factory specs at the dealership. For those who do not want to work on their own cycle, I recommend factory-trained techs and tooling. OEM parts are always a plus, I'm a frequent customer for genuine Honda and other brand parts... I enjoy several things about motorcycle work. Since I like to spin wrenches, and many of us do, motorcycles are a great place to build and retain skills. Motorcycle work is far less cumbersome than automotive and truck work, although I'm well schooled and trained at both. At home, our neighbors are way more comfortable watching me tune a dirt motorcycle than dropping and rebuilding an automatic transmission from a 4x4 truck...So much for suburbia, anyway... The additional benefits of working on your own cycle, especially a dirt bike headed to remote places, are self-sufficiency and acquiring troubleshooting skills. You know your way around the motorcycle and can quickly become oriented for repairs or emergency fixes in the field. My earliest sense of motorized accomplishment was the restoration of a 1955 Cushman/Allstate scooter. The $8 "discovery", with a loudly knocking motor, tossed its connecting rod on my first ride—the loose rod snapped the camshaft in half and destroyed the iron block casting. The incentive for bringing that scooter back was to ride on Nevada's streets and highways, legally, at the age of 14. That Cushman scooter launched my lifelong interest in motorcycle, automotive and truck service work and technology. Fifty years later, I vividly recall passing my written license exam and the satisfaction I had with the engine and other work to get—and keep—that Cushman running. I still enjoy motorcycle work, and to celebrate my 50th year of riding and working on road and dirt motorcycles, I invested in a Harbor Freight 1000# motorcycle lift...Check out the forum post at: http://www.4wdmechanix.com/forums/index.php/topic/83-harbor-freight-1000-motorcycle-lift—best-buy-on-the-planet/ Moses
×
×
  • Create New...