Trying to figure out whats wrong with it, It was at a shop, The shop said they replaced the battery and checked the valve gap and it was ok, But it still does not start, I have checked the timing and think I set it right, When the T is seeable in the hole the cam is at its mark? Is that correct? I have double checked the valves again and they are fine, It has spark, Plug is dry after cranking for a bit. Won't even fire if i shoot gas down the plug hole and then try. Any ideas? I need to report back to the owner before I purchase this atv.

 

Does it have compression?

 

No or low compression will also effect fuel getting into the motor, low or no vacuum. Also maybe a bent valve. Leak down test would be best to determine that.

 

It had 90PSI but I forgot to open throttle wide open during the test, I found that the intake valve was leaking bad due to chips in the sealing surface, Could this cause the problem?

 

90 psi is really bad, probably the main reason it wont start, if the valves are bad, good chance the rings are worn too, probably time to tear down the top end and freshen it up.

 

I forgot to mention, Another reason I think the compression lowness is due to the valve is it was pushing pressure out the carb, Enough that I could not keep my hand over it when cranking

 

 

If you are pushing air back out the carb, either the valves are way too tight, so they are hanging open and leaking compression back, or the seat or valve surface is so bad it is letting pressure back out the intake, looks like time for a new set of valves and springs, and the seats should be resurfaced.

 

I am planing on it, For what its worth, I think this engine has been rebuilt before, Has gaskets that i am pretty sure are not stock. I am going to get a shop to do the head/valve work

 

Hopefully for under 100