help with compression ? wont start

[seanmccullough67]

okay how much compression should my warrior have, all i have is a full exhaust and its jetted. we did a compression test and said it has 90 psi or whatever it is. how much should it have. and i took it to my local yamaha shop and they told me its my valves, could that be why i have low compression and why it wont start? before this it would start right up and run great for about a half hour, id shut it off and it wouldnt start, then id let it sit for about 20 minutes and it would fire up and run like hell again:argh:

 

[bones]

it depends on compression ratio but the book says 114 min and 128 max.... mine is 153 and i have heard of some at like 170

 

[seanmccullough67]

so its probly a bad thing i only have 90 lol

 

[duneracerweston]

Check valve lash and a 366 at 11:1 its usualy over 200psi