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