xr650L problems-pics of damage

Im new to 4 strokes so im in need of some help heres that happened. I was just cruisin the other day at 55 and it started to bogg down on me so i gave it gas and still bogged. Pulled over pulled in the clutch and now it wont start. When i try and start the bike it seems like its turning over much faster than normal. Also there is some white bluish smoke commin out of the exaust. It seems like the exaust is sucking in too? I cant fit my compression tester in there to test it its too small of a space. Yes it had gas, its getting good spark, and wouldent start with eather. I tried to look at the timing chain but it seems i have to remover the motor to do this. These bikes have a decompression unit on them i was told, do they go bad? Any help or guidence woule be great



You may want to add in what year XR650L, miles and mods.

Presently thinking maybe timing chain jumped.

I think you need to get the tank off and pull valve caps and turn over, see if everything is still moving and then go from there. Sounds like something definitely let go. Your prolly in for some work though, good time for a rebuild if you got alot of miles on it.

I have heard of only one XRL which had the auto-decomp go bad.

Unfortunately, it happened in the middle of 5-miles-of-hell in Utah (5MOH's in Utah, right?).

Anyway, if you got a bunch of new smoke, sounds more serious than the decomp.

You can bypass the decomp, BTW, by loiosening the pproper exhaust valve. Which one, and by how much, is in the shop manual under the instructions for doing a compression test.


Its an 03 650l and i only have 4000 miles on it. It has exaust, jetting, air filter thast it and thats been done since 1000mi. I was able to see the timing chain and it was tight, but could it still have jumped? I took off thoes caps and turned it over and everything was moving.

Have you checked compression yet? Maybe you burned a hole in the piston.

I'm guessing there's a hole in your piston.

...if you decide to part out, I need a complete head and valve cover!:thumbsup:

Seriously though, I feel your pain and hope you get it sorted. (still serious about the head and cover tho)

Its an 03 650l and i only have 4000 miles on it. It has exaust, jetting, air filter thast it and thats been done since 1000mi. I was able to see the timing chain and it was tight, but could it still have jumped? I took off thoes caps and turned it over and everything was moving.

need to get a manual and set it at tdc to see if the marks are all where they should be. wont fire up at all now?

Nope wont fire at all. Im gonna tear the motor out tonight sice i cant get the head/valve cover off cause the bolts hit the frame when u try and take em out. Then ill try to line it up, thanks by the way for helpin me out

let us know what you find and show pics if you can!

I had a valve seat drop on mine. It was an intake valve and the symptoms were similar to yours except mine still ran, barely. Felt like the timing was 180 out but that isn't possible without catastrophic damage. All it cost me was a head job but since I was in there I replaced the piston with a wiseco 10.5-1 and did the cyl work, new rings, etc. Runs like a champ now with about 25% more oommph. Could be the same, only way to tell is by pulling the head. Getting the motor in/out is only about an hour so it's no biggie.

Ahhhh.......tore her down and well the pics explain most of it. Trying to find out why it blew though. When I first took it apart there was a lot of sand and dirt built up on the head and head gasket i took a pic of it. It looks like where that air suction valve comes into the head, But doesnt that only circulate air into the exaust ports? Its only scratched up on the intake side. Not shure yet gonna dismantel it more soon.





Looks like you sucked sand in and really wore down the cylinder and piston:eek:

I am going to venture to guess that the bike was running just a tad hot. I just had my bike fail the same way. Pulled over opened up the oil reservoir and smoke was pouring out! Let the engine cool for about 30 minutes and fired right off but with lots of smoke so I called for a pick-up to come get me. :thumbsup: After tearing it down I found that the piston had also rubbed the intake side of the cylinder. :thumbsup:

As for the little area of dry sand, if you scrape that off the cylinder you will find that there is no port there just solid aluminum. There is however a matching port in the head that is just part of the casting process. All of my XR's have this hole and none of them suffer from dirt being in there.

the dirt is because the head is porous around the spark plug hole. When I was cleaning mine after a exhaust valve seat broke apart, my old head and the new one both had the same hole.. it ends at the gasket so it just makes a mess when the gasket is disturbed, it's not what caused the scoring because it is sealed by the gasket. imo looks like you ran it out of oil or maybe a hole in the airfilter for debris to get through did it

Take a look at the airbox to carb rubber boot. I had mine come off once, while riding at the Pismo beach dunes. I guess that I got lucky and caught it before major damage happened, because when I opened her up the damage was minimal.

When I bought my 94' (used and abused) the previous owner had installed a flat slid carb on it. The carb was set way too rich and washed the oil off the cylinder wall. It looked the same as yours. The oil also smelled like gas.

The plus side is I got to do an overbore and mild port job on the head. BIGGGG difference. All the wife knew was I had to fix the engine.

She did not need to know I was installing Kibble White guides and valves, Hot Cam stage 1, larger piston. Get it fixed up and keep us posted.


make sure you replace the oil pump!!!!! could have failed. hows the top end look? also check your oil lines for kinks. clean the downtube screen also.

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