2002 XR650L, 39,000 miles, rebuild report

Hello all,

In case someone's interested in the condition of a high-mileage XR, I'll post a rebuild thread with pics (if I can figure out how to attach them). Don't hesitate to post questions, I'll check this thread occasionaly to answer them.

The bike has 39,000 HARD miles on it: the first 30,000 of those miles I burned exclusively waste av-gas (100LL, because it was free!), the last 9,000 miles with pump gas (my sump fuel supply ran out!). Most of the miles are on the street but I get offroad occasionally. It wasn't burning oil but I could tell the valve stem seals were letting some oil past - a little puff at start-up.

I changed oil and filter every 5,000 miles and used Mobile 1 synthetic. The chain and sprockets are XR650R front 15T (C.S. splines are like-new) and XRs Only rear aluminum 48T, D.I.D. X Ring chain, OEM paper air filter, uncorked and jetted for 5,500 feet elevation.

I'm installing a 102mm JE 10.5:1 piston, a HotCam, and a new clutch. I started the project yesterday afternoon and it should be running by tomorrow.

The left case had to come off because the return/tension spring for the clutch throw-out lever had broken (I'd rigged up an external spring but wanted it OEM). Everything inside the left case was good-as-new.

The exhaust pipes showed that the jetting was pretty darn close, a white ash inside with no appreciable carbon. The valve cover comes off the back of the head after the intake is taken off the cylinder. The cam center-journal showed no wear, the cam lobes showed only polish-type wear. the rockers showed only polish-type wear, everything's in spec. There was no sludge of any kind. The cam chain tensioner arm showed only cosmetic wear, there was no groove of any kind. The cam chain is longer than it should be but was not even close to causing any sort of problem.

The head had a bit of carbon but the valves seats look new and the stems/guides are in spec for new valves. I put some fluid in the valve pocket to see if they were sealed and the fluid did not leak out. I will lightly lapp the valves and re-use them. The outer valve springs are in-spec, the inners are all are about three thousanths too short. Since I don't have new ones handy, I'll re-use them and replace after another 40,000 or so...

The cylinder still had the original hone marks visible with light scuffing on each side of the wrist pin. The ring groove and taper are negligible and the upper connecting rod dimension is in spec.

That's it for now, I've gotta get back out there and install the new clutch while the cylinder is getting bored/honed. I'll try to attach some teaser pics and finish with a full report later.

Randy

P.S. It looks like I can't directly attach pics, maybe someone here can help. Meanwhile, I'm headed back to the shop...

Update: original clutch was the same thickness as the new one, it hadn't worn a measurable amount (using my high-speed Harbor Freight digital micrometer). The clutch basket had no grooves in it either, just some marks where the plates have been engaged.

In short, except for the head, the engine components look like they've just broken in.

I've got a full series of pics if anyone is interested, I just need a way to post them.

I'll post a follow up on the performance changes once I get it running.

Randy

wow good to hear. where can I get waste avgas? :smirk:

Update: The bike is assembled and I just finished putting the first 30 minutes on the new top end. Wow! It's smooth, makes great power, and pulls forever. The jetting is spot-on, no need for any changes. The starter only has trouble turning the engine over when the piston is positioned just prior to TDC, it still starts but it slows waaaay down. If the piston is anywhere else, it cranks through without slowing.

That's it for now. I'll be happy to field any questions.

Randy

P.S. n16ht5, you can access waste av-gas if you work at the airport and have the line crew put their sump fuel in a barrel. Then you can pump it out of the barrel and store it at your house. I had it made until the company bought a recycler for waste fuel. Jet fuel in my Cummins (near 50,000 miles) and Av-gas in my bike (30,000 miles) made for cheap transportation.

What do the countershaft splines look like? To add pictures you'll need to upload them to a photo hosting site (like photobucket) then put links to them in your posts...To have them show up on your post use the [ img ] [/ img] tags.

man, if i get 30,000 miles out of mine, ill be dead. my 2002 only has 3200 miles right now. i guess i better get out and ride. summers here and gas is high, looks like i got a new ride to work. gonna look funny trying to haul plywood and 2x4's on my bike. keep it coming.thanks,IRR

Wow, original hone marks on an air-cooled thumper with almost 40,000 miles on it? Maybe there's something to that there synthetic stuff.

Mcnutty, the countershaft splines looked brand new. I didn't take a pic of them because there's nothing to see but I've got quite a few pics of the rest of the engine.

Bibleman, yes, I believe there are big benefits to be gained from running synthetic oil. My engine speaks for itself - nearly 40,000 miles and most of the parts showing zero wear.

Now, back to the pic-posting attempt.

Randy

You didn't say for how long you have been using the xr650r countershaft sprocket or is this something new with the rebuild, also have you always used a 15 tooth?

Ferdinand,

That's a good question. I ran O.E.M. countershaft sprockets, 15 tooth, until just a short time ago - maybe a few hundred miles. At that time I put an XR650R C.S. sprocket on. As I've said before, the splines were like-new. Until discovering the thread on 650R countershafts, I firmly believed that OEM was the way to avoid shaft damage (not lugging the engine is the number two way).

The reason I avoid less than 15 teeth is because of the reduced radius on the countershaft. Chain wear and swing arm buffer wear is reduced when you keep the countershaft sprocket on the large side. Gearing is easy enough to change with rear sprocket gearing.

I'm not arrogant enough to believe that my bike - or my opinion - is so terribly important to anyone. It's just that my bike has so many miles on it that there are some lessons learned for anyone that has questions.

Randy

how often did you change the oil?. maybe ill switch... what weight/brand are you using? do you work at a commercial airport?

n16ht5,

I changed the oil about every 5,000 miles. Primarily Mobile 1, sometimes a mix of Mobile 1 and whatever I had on the shelf - but always some mix of synthetic. 10/40 is the weight I use most.

Yes, I am based at a commercial airport.

Randy

This is all interesting info thanks for sharing, it's good to hear info about a

650L that's paid its dues with lots of miles usually you'll hear about the miles, but not about the details and history.

thanks randy, ill be switching to synthetic

Update: The bike is assembled and I just finished putting the first 30 minutes on the new top end. Wow! It's smooth, makes great power, and pulls forever. The jetting is spot-on, no need for any changes. The starter only has trouble turning the engine over when the piston is positioned just prior to TDC, it still starts but it slows waaaay down. If the piston is anywhere else, it cranks through without slowing.

That's it for now. I'll be happy to field any questions.

Randy

P.S. n16ht5, you can access waste av-gas if you work at the airport and have the line crew put their sump fuel in a barrel. Then you can pump it out of the barrel and store it at your house. I had it made until the company bought a recycler for waste fuel. Jet fuel in my Cummins (near 50,000 miles) and Av-gas in my bike (30,000 miles) made for cheap transportation.

You could look into istalling a mechanical push in compression release like the ones that they use on high compression choppers. They are using them alot on the cr500s & with great results also. A friend of mine is running a 107 inch v twin & went through 3 high torque starters before he had them install the mechanical compression release & now he's running the same starter for well over a year now & it starts soooo much easier like its a stock motor.

Hey Randy, exactly which Mobil 1 are you using? The bike-specific stuff, or one of the others ? Thanks.........:smirk:

I always suspect a "soft" battery in those situations.

Even a fresh charge won't help if the battery cannot

put out the amps. Taking a voltage reading WHILE cranking

will tell the story.

But check/clean ALL connections AND the resistance

of the starter solonoid contacts. Who knows, with

that amount of miliage and now more compression,

it could even be the starter brushes. Not much more to it.

Bob K

Jimbo1143, I discovered a technique (old post from this board) that gets around the decompression issue. The engine will crank normally if the kill switch is turned off. After it makes a revolution I turn the kill switch back on and it starts as if there was a decompressor. This is only necessary if the engine is hot and it needed to be cranked immediately after shut-down.

Brocephus, I use the standard Mobile 1. Nothing special.

Bob K, thanks for the suggestions about batteries. Got it figured out, though, see above.

One more update for folks who are similarly configured: The engine had some light flutter-type pinging at mid-throttle when it was hot; after a ten mile high speed run, for instance. Dave's Mods come through again! The needle was raised by .020 thousanths, Dave's Mods call for .030. I've changed the needle shim, the pinging is gone, and it appears that a 10.5:1 ratio is good for pump gas at 5500 feet.

Randy

Edited by flyairam

Hello all,

In case someone's interested in the condition of a high-mileage XR, I'll post a rebuild thread with pics (if I can figure out how to attach them). Don't hesitate to post questions, I'll check this thread occasionaly to answer them.

The bike has 39,000 HARD miles on it: the first 30,000 of those miles I burned exclusively waste av-gas (100LL, because it was free!), the last 9,000 miles with pump gas (my sump fuel supply ran out!). Most of the miles are on the street but I get offroad occasionally. It wasn't burning oil but I could tell the valve stem seals were letting some oil past - a little puff at start-up.

I changed oil and filter every 5,000 miles and used Mobile 1 synthetic. The chain and sprockets are XR650R front 15T (C.S. splines are like-new) and XRs Only rear aluminum 48T, D.I.D. X Ring chain, OEM paper air filter, uncorked and jetted for 5,500 feet elevation.

I'm installing a 102mm JE 10.5:1 piston, a HotCam, and a new clutch. I started the project yesterday afternoon and it should be running by tomorrow.

The left case had to come off because the return/tension spring for the clutch throw-out lever had broken (I'd rigged up an external spring but wanted it OEM). Everything inside the left case was good-as-new.

The exhaust pipes showed that the jetting was pretty darn close, a white ash inside with no appreciable carbon. The valve cover comes off the back of the head after the intake is taken off the cylinder. The cam center-journal showed no wear, the cam lobes showed only polish-type wear. the rockers showed only polish-type wear, everything's in spec. There was no sludge of any kind. The cam chain tensioner arm showed only cosmetic wear, there was no groove of any kind. The cam chain is longer than it should be but was not even close to causing any sort of problem.

The head had a bit of carbon but the valves seats look new and the stems/guides are in spec for new valves. I put some fluid in the valve pocket to see if they were sealed and the fluid did not leak out. I will lightly lapp the valves and re-use them. The outer valve springs are in-spec, the inners are all are about three thousanths too short. Since I don't have new ones handy, I'll re-use them and replace after another 40,000 or so...

The cylinder still had the original hone marks visible with light scuffing on each side of the wrist pin. The ring groove and taper are negligible and the upper connecting rod dimension is in spec.

That's it for now, I've gotta get back out there and install the new clutch while the cylinder is getting bored/honed. I'll try to attach some teaser pics and finish with a full report later.

Randy

P.S. It looks like I can't directly attach pics, maybe someone here can help. Meanwhile, I'm headed back to the shop...

Are you running any type of added oil cooler on your bike? Do you monitor temps of the oil? Just curious, as I find these threads super interesting, and informative. I am also a huge fan of mobile 1 oil, and just started running it in my XR650L at 2,500 miles. I realize this thread is a little dated, but so interesting to me.

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