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Moses,


A friend of mine bought a 2006 650L a couple months ago, I went with him to inspect it and pick it up. It's been problem free up until recent. About a week ago he told me the chain slider somehow came off the top of the swingarm and was flapping off the bottom. No big deal, bought a new one and I watched him install it correctly. 5 miles down the road and the top came off and went through the front sprocket. I looked at everything, mounting hardware was still intact, chain is a touch loose, but nothing glaring. Any experiences losing a slider, let alone two in as many rides? I can't say that I have.

So we turn around to head back to my house and the bike makes it a couple miles before dying. I get it started, figured maybe it was operator error as my buddy is new to bikes and such. Then it died again another mile down the road. It would start momentarily with the choke on, I ended up running home to get my truck, the bike was done. I had him order a carb kit, I'll start there with a rebuild and replace the plug as it looks overdue. I think this should solve the non-op issue.

At the end of the day I would say the slider coming off saved our butts, because otherwise we would have been way up the North Cascade Highway with a bike that didn't want to run.

 

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Hi, 53HiHood...The slider failure could be misalignment of the rear wheel/axle.  Is the chain running straight across the slider?  Otherwise maybe too tight on the chain adjustment?

The second issue does sound like fuel supply.  I've had these kinds of troubles from ethanol/gasoline setting up for too long, clogging the jets.  It can be the strainer in the tank or the carburetor.  A sticky float needle does this...A kit at the carburetor can solve these issues, dip the carburetor to clean out passages and be sure to inspect jets for clogging.  They need replacing if you find hard buildup, I did this on the pilot for my XR350R.   Inspect the tank screen at the petcock valve.

Moses

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I had my buddy order a carb kit and I gave it a thorough cleaning and replaced all consumables. We also replaced the spark plug while we had the tank off. I haven't checked in the tank but we'll do that. The bike fired right up afterwards.

As for the slider issue, I checked tension and alignment, everything checks out. The seller makes the sliders, and had commented that it was maybe a bad batch. I sent the bike on a short test ride and so far so good. I'll have him do a couple more short trips before hitting the open road. Thanks for the insight.

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Glad you have a likely solution and a riding buddy!  Sounds like the remedies worked...I like the idea of short test rides before the longer adventure!

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The 650 is back in my shop. My buddies last ride ended with what sounds like the engine seizing. I wasn't there so I'm not sure what the bike was doing. We'll be digging into it this week.

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We pulled the top end this evening and it looked as I expected it would. The cam was dry, the oil is super dark, and the piston was seized. Pulling the cylinder exposed the damaged piston and seized wrist pin. Let's hope the crank is ok. I'll have to split the cases to thoroughly clean the bottom end.


Anyone have their top end seize like this before? The oil level was sufficient. My thoughts are failed oil pump or a blocked oil passage.

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53HiHood...Definitely lack of oil flow...Restricted flow, an obstruction, running the engine low on oil or a blocked passageway, clogged oil filter, failed oil pump, things you know.  Gasket or dowel misalignment at the barrel base or head is rare but a possibility.  Has this engine been apart before?  This is a rugged, older wet-sump oil system design that is not particularly failure prone.

If the bike set up for long periods, oil sludge is a possibility, it's great that you're tearing the engine down completely despite the work involved.  The clutch discs need cleaning and inspection...All passageways need cleaning...The sump screen on this wet-sump lubrication system could be clogged, maybe the origin of the trouble.  I'd look closely here...

Please share pics of your findings.  I'm curious what you find to be the cause.

Moses

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I attached a picture of the piston and bore, both are wiped out. The rod is seized on the crank as well. The bike did sit a lot during the summer and I also don't believe the oil had been changed since this Spring. The owner is new to bikes and not mechanically inclined, which is partially why the bike is in this condition now. Lesson learned for him, when the bike starts making noise don't keep riding. I haven't split the cases yet, I've been working on my own bike. I'll post pictures once I do.

It doesn't appear that the engine has been apart before.

I'll be sending the head, cylinder, and crank to millennium technologies. The cylinder will need a +1 or 2mm overbore. I think a slight bump in c.r. and stage 1 hot cam wouldn't hurt. A valve job and new con rod and trued crank will also been done. Any input is welcome.

IMG_20171205_220217079.jpg

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You called this one...oil starvation and seizure.  If you can get by with 1mm oversize on the bore, that would be better than +2mm.  You're planning right with a complete teardown, bearings could be scored from lack of oil.  It will not surprise me if you find the sludge/sump screen filter clogged.  Clutch lining would be one type of floating debris that can wreak havoc with this filter.

Rubber seals get replaced and check for warp and other issues.  Check the clutch plates and basket, the usual stuff.  This engine was severely stressed, you want to inspect everything, including the oil pump for scoring and clearance issues.  Any springs should be checked for standing height at the very least.  Look for discoloration and other signs of fatigue.

Your friend's XR650L could benefit from a HotCams Stage 1 upgrade.  I'm thrilled with this on the XR650R and even more thrilled to have eliminated the factory auto-decompressor kick starting mechanism.  Does the Stage 1 XR650L camshaft eliminate the auto-decompressor for kick-over?  I use the handlebar manual de-compression lever/release to 1) pinpoint TDC on the compression stroke and 2) bring the piston over TDC just slightly.  Release the lever and kick through with full compression.  Tuned properly, the engine should start first kick 90% of the time—two kicks the other 10%.  Unheard of, supposedly, for an XR650R!

Looking forward to your pics when you get the time to tear the engine down completely...

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We’re getting close to reassembly. I had to send the head to Engine Dynamics in Petaluma for cam journal repair. There is a journal machined into the head and when the oil level or quality is insufficient bad things happen. I guess it’s not uncommon for these bikes to have oil starvation issues when ridden at highway speeds for long periods. Not a cheap repair, about $200 to weld the journal to build it back up and then re-machine it. But cheaper than the valve job, $300 is a bit steep for a basic 4 valve head. I should have just had them do the repair and sent the head with the crank and cylinder to Millenium Technologies as they charge about half as much. The crank may or may not be serviceable. Apparently the gear that’s pressed onto the crank can be a real pain and the shop says it’s usually 50/50 with getting the gear off. It’s been at least a few weeks since I sent the cylinder and crank in, no word on when they’ll be done. 

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53HiHood...A new Honda cylinder head casting is still available.  I'm wondering whether a new casting would be cost effective?  

I looked up a popular online Honda parts source and pricing.  The Genuine Honda cylinder head, part number 12200-MY6-670 for a 2006 Honda 650L (49-State model) complete with valve guides, is $458.87 from one source.  You would still have valves, springs, retainers, the camshaft and other parts to consider.  Not sure whether the guides are installed and the seats cut and finished on this head assembly.

Interesting look at aftermarket service options...

Moses

 

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Engine Dynamics did a great job on the head repair. I wish I had the cylinder and crank so that I could assemble the engine. I'm hoping those will be finished and shipped today, but I've been hoping that for a month now. I did look at new head options, as well as new cranks. These 650L's are not the cheapest honda's to rebuild. At least the cylinder has a sleeve that can be easily bored and honed, otherwise total cost would be near the value of the bike itself.

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Yep, it does add up.  The good news is your attention to detail and a lucky friend who will be the recipient of a very reliable XR650L air-cooled engine when you finish this project...

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I ended up getting the crank the week before I left. Millenium Technologies forgot to include the cylinder and piston kit in the shipment, which makes twice this winter they did that, and I got that stuff just days before I had to leave. A couple long nights and I had it all assembled minus a couple things. My buddy will have to finish putting the bike together and do the initial start up and break in without me. I’ll walk him through that though. 

I will say this, I’m shopping for a new machine shop. I don’t like to stress over things when I’m working on bikes. Turnaround times in excess of a month and misplaced parts is not acceptable.

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Understood...Your experience is insightful for others...Enjoy your new "home", Durango is a great base for bikes and outdoor activities.  I know your work is demanding, but when you do have the time, the area will be perfect for your Honda CRF (dirt and snow both) and the CJ3B!

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An update on the XR650L, my buddy(the owner) finished putting the bike back together, which was really just installing the exhaust, battery, and a few other little things. The aftermarket cam does not have a decompression feature so he had to install a more powerful battery, I’ll have to check with him on the model. Other than that, he was really pleased with the power and responsiveness of the new engine. I have not ridden it myself but I’ll get on it att some point this winter.

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53HiHood...Always good to hear your news!  You're finally past the fire season, which must have been exhaustive this year...Are you still based at Durango Area?  Any snow riding with the CRF planned?

Moses

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I’m not in Durango anymore, that was just a 5 month temp reassignment. I’m back in the great PNW! The snow is finally falling so I’ll be riding the little CRF soon.

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