All kinds of top end noise on XR 650L

I took my XR/L out for a good dirt thrashing in the Sierra's this weekend, and all of a sudden, my bike started stalling allot, and then I got all kinds of valve noise from the top end. Finally, the bike would idle, but with So much noise, I shut it down. What is it? I understand there are some cam chain tensioners that could be the issue from my buddies, but has anyone had this problem? Further, I understand you have to take the engine out of the frame to even get the valve cover off?

Anything can help me narrow down what to even look for would be great.

PS: it's a 2000 Xr650L with 5000 miles--yes there is plenty of oil, with only about 1,000 miles on the oil:cry:

I would think about taking off the valve cover to inspect the cam, cam chain, and rocker arms. There are plastic guides for the chain that are in the cylinder/cam chain area. Check to make sure they are not broken. If you broke anything, you need to make sure that you find where the pieces went. Hopefully its something simple.

With the valve cover off, try to rotate the cam by hand. Go back and forth to see if there is any play inthe chain. That thing is supposed to be really tight so that it has zero backlash (moving back and forth should try to make the engine move with it). Be careful when tightening bolts so you don't overtighten stuff. I'm not sure if you need a bead of silicone on the valve cover when you put it back on.

If everything looks good, then maybe its something else.

Hopefully some more XRL owners help out here.

definately pull the valve cover and check your valve train. probably a lubrication issue(i.e. bad oil pump). i am doing a hotcam in mine right now so i will let you know if the valve cover can be removed with eng. in frame. right now it doesnt look like it cuz there is one 10mm head bolt in the center that is blocked from being removed by the frame.

Yes if you fiddle around enough the bolt will come out and you can get the cover off without removing the engine.

I doubt that the cam chain tensioner is your problem. My tensioner went bad and it was kind of subtle. It was a rattle caused by the chain hitting the case and it was only noticeable just off idle. At high speeds the engine noise overwhelmed it. My bike also had a lot more than 5000 miles on it.

Check your valve clearance or get that cover off. I'm guessing that you are going to find a toasted cam and/or rocker arms. It also could be a failed valve seat. Been there done that. I first noticed reduced power and then it quit as soon as I let off the gas. I had to adjust the valve clearance about every 10 miles until I got back to the truck. In my case the cam and rockers were OK, but I had to have valve seats made and installed. Most shops can't do that. I had XR's only do that woks and the head has been good ever since.

Let us know what you find.

Great info all the way around. I really appreciate it. To be clear, the valve noise is a "ticking". For a while, it sounded like something more. But as I could get it to idle, any noise or other issues settled into a simple ticking sound. Power was ony slightly off, but it ran rougher and smoked more

Ticking is probably just out of adjustment. Still, I would thoroughly inspect your rocker arms for cracks.

the auto decompressor would make a ticking noise on my L at times.

dont have to worry about that now cuz the hotcam i put in doesnt reuse it!

Being that it is an XR650L I can't say for certain that the valve cover can be removed with the engine in-BUT-if the 650L is like the XR600R then it can!

I have an XR600R and the valve cover will come off with the engine still in place.

In fact, you can pull the head, & the jug with the engine in the frame.

Now on to your specific problem... Does this bike still have the auto-decompressor on it? If so, definitely check to see if the internal parts of the auto-decom are still in place & working.. It may be a long shot but if the system is failing, it is possible that it could be making the ticking noise you describe, and further, if it is actuating when it is not supposed to, it can cause the stalling you are experiencing. I wont venture a guess either way, but one thing is for sure, that cover is going to have to come off to inspect the valve train, and the auto-decom.. So, what are you waiting for? Pull the v/c already!

yes i was able to remove the valve cover last night once the carb/intake boot was off.

And the verdict is.........?

Dropped a valve seat?


Enquiring minds (with XRLs) want to know!


Exact same issue as mine. Dropped a valve seat. Machine shop replaced that and another one and replaced all 4 valves.

Just got a new cam in today so hopefully going to put it all back together again this weekend.

should i say valve adjustment more often? or this JUST happens.

the valve seat failure is very common on all XR/XL engines that have been round the block a few times! Think its the heat and compression that must do it.

the smaller domed heads of the 600R and XL600 seems to be worse as I guess they have more compression...more heat etc...

so by going with a hicomp piston are we inceasing the probability of this failure?

I don't know if this is right, but I feet that this is a heat related failure. At a certain point the aluminum gets soft. The heat softened aluminum deforms and the valve seat basically falls out. It is only pressed into the head.

Higher compression pistons make more heat so I would say that they increase the likelihood of this failure. How you run your bike makes a big difference in the heat the engine experiences. Going down the highway usually keeps things cool because of the wind speed. I see the most heat on crazy singletrack mountain goat climbs where the bike is in first and second gear. Lots of throttle, but very little speed so there is not much cooling.

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