06 250x engine sound

I bought a 06 crf250x the other day in mint condition. The only thing that's worrying me is the engine sound at idle. The bike runs awesome, but at idle it has a ticking sound every once in a while and kind of sounds like something's winding inside the engine. Could this be the stator? I have a 06 250r and it doesn't make these noises. I figured it had to be the stator. It also doesn't idle too smooth, every once in a while the exhaust will go from the normal sound to a "brrrrrr" (rolling your r's with your tongue sound) Other than the weird sounds it runs amazing and starts right up!



I would pop the valve cover, double check the valve lash and that the decompressor system is working correctly.


Also check visibly for signs of wear on the rocker arm and cam lobes.



I have quite a bit of sound at idle as well.  I was wondering if it may be the automatic cam chain tensioner.  Are they an issue on these bikes? 

No, the 250's are pretty quiet.  With the 450's though, it's sounds like you have marbles in there.


A "ticking" is not a usual sound.    Could very well be the cam chain slapping around and it would probably be a good idea to check if the automatic tensioner is all the way out. 


If so, new cam chain (and possibly guides) would be in order and then a big pat on the back for being observent and probably saving youself a ton of money.


A cam chain coming off can be a bad thing :(



compared to DOHC motors the unicam is noisey, nothing wrong just less mass in the head to mask the noise.  The exhaust rocker roller end makes a lot of noise.Normal. If the idle speed is too low the carb slide rattles and makes noise. And the auto decompressor can make some noise at cranking or dieing.   If you set the exh clearance a little tighter than spec you can quiet it up some, just make sure the roller-cam interface has clearance. Down side is the auto decomp will make more noise set this way,   a wash I guess.  Open air box will make more noise, and a corked up stock pipe makes the engine sound noisier.

Edited by highmarker

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