Weird noise coming from 2012 YZ250F

Hell i desperately need help,
I am going riding in 2 days and i have this terrible noise coming from my YZ250F especially when i rev it (sound like a high pitched whining noise, not like the good old deep rumble of a 250f) it sounds like its from the timing chain area. I have checked the chain tension and it is adjusted fine. Compression is okkayyy but a bit low. However the most concerning is the bike won't really idle. When i first got it i would start it and it would idle for 1 minute then stall by itself. Since then i have adjusted the Air/fuel mixture and it has helped a bit but still not great. I suspect something to do with the vales but i don't know how to do that. I just really want to get rid of the noise its very annoying and scary. Am i panicking or is this normal ??

1. Weird ticking, hitting or pinging noise
2. Compression is a bit low
3. Bike struggles to idle without stalling.

Any information will help. thankyou
I would try adjusting valves. It is not difficult if you are able to use tools and follow instructions. If not, that’s ok. But you are going to have to take it to a qualified mechanic.


Staff member
How did the ride go? It may be nothing, but good to be paying attention to noises and abnormal operation.
-BIG DAN:thumb: