I've only got about 25 miles on my KLX but even from the first start-up, I have been hearing what I think is excessive tapping of the valves. Has anyone else had this problem? I thought after I rode it for a few miles, the noise would decrease or go away completely, but no luck yet. Should I take it back to the dealer? I'm no motorcycle mechanic but it sounds like the valves need to be adjusted.

 

A couple of simple things to check first:

With the engine running, get down beside it and try to identify more specifically where the sound is coming from. It may be as simple as one or both of the exhaust stud nuts being loose where the header pipe connects to the head. A small leak there can sound just like valve clack.

Also, your bike is equiped with a smog device for the EPA called an Air Valve. It's setting on top of the head beneath the tank and it opens and closes on every revolution of the engine. It can also make a clacking sound. I highly recommend removing that anyway so you might start with that (instructions posted elsewhere on this forum).

If neither of those seem to be the problem, then it might be worth taking it in to have it checked if it bothers you but having them make noise (because they're slightly loose) is really not a problem and just means you'll have longer before they get too tight and have to be adjusted.

 

I appreciate the information. I'll try that out this evening and see if I can locate the exact source of the noise. I was worried that if it was the valves, that it would do some damage to them if i just left it alone but you have cleared that up. Thanks

 

I have noticed this noise too right from the start, and now with 600 miles on it I wonder if I should have the valves checked. Is that what the device protruding out of the cylinder is with the 3 blots on it?

deej

 

The valves are under the cylinder head cover. Here's a shot, bolts removed:



Here's what's in there (cover off):



To check the clearences, remove the crank case plugs and rotate the crankshaft counterclockwise until the valves open and close one cycle, then about 1/2 a turn more until the "T" TDC mark lines up in the notch:



Use feeler gauges to measure the clearences in the inlet and exhaust valves (2 of each). Measure between the cam lobes and the valve lifters (the cylindrical can below the lobes):



-Brian


EDIT: update photo links

 

Great photos!

BTW, did you really have to remove the coil to get the valve cover off? If so, that's yet another reason to move it up like I did during the IMS tank install. Wish I'd taken a picture of the re-mount. I will next time I pull the tank.

 

Thanks!

Yes, though a better mechanic than I might be able slip the cover out without doing that. The cover has to rise up a good bit, especially on the side with the cam chain to clear those components. The throttle cable guide is kind've in the way too, but it is flexible enough that you can shove that aside without having to remove it.

Since I still have everything apart, I rechecked my clearences with the engine dead cold like the manual says to do (it was slightly warm when I checked them before). I have one inlet valve that seems like it might be a little out of spec on the low side. All the other valves seem borderline on the low side. I'm now debating whether I really want to adjust them myself, or take it to the shop and have them do it. I'm pretty sure I can do it myself, but I've never done an adjustment before so I'm a little hesitant. I'm not in a great rush, so I may just go ahead and do it myself, taking my time. I just googled for some shim kits and it looks like to get a few of every shim, you'll need to spend about $85. Having the full kit is nice since you don't really know which one(s) you'll need until you take it apart and see what shim is currently installed. What does the whole job cost at a typical shop - anyone have an idea? Is it a lot more than $85. I suspect so, so it may be worthwhile economically to DIY.

Another advantage of doing it yourself is you know it's done right. Pulling the cam shafts off and putting them back on with proper timing doesn't really look too bad. The KLX250R service manual does a good job of describing the process.

-Brian