Got a non-starting Eton (2006?) CXL150 ATV .. Had spark.. Turns over.. Won't run.. Noticed fuel coming out of intake while cranking.. Did compression test showed zero.. Pulled head and cylinder cylinder showed scorched and fused rings into the piston on one side.. Put new cylinder and piston and rings in and put old head back on .. Compression test showed 125 psi.. However LOTS of air still blowing out intake port.. Did leak down test with 100 psi input .. result of course showed zero with all air blowing out through intake.. I had it on TDC on compression stroke both valves closed.. Took head off looked at Valves by visual inspection and everything looks okay just by visual inspection.. No visual cracks.. No daylight in valve ports.. Sprayed contact cleaner in ports .. no leak through valve.. So where could all this air be getting out the intake port from? Anything else I can do or look for short of gettin this hard to find head? Thanks!

 

Did a halfway valve grind and tried the leakdown test again on a cold day and got a 70% reading.. At 50psi i got 35 on 2nd gauge and at 100psi I got 70 .. For 70%. .Didn't feel any air coming out of intake, exhaust, cylinder head gasket area, or crankcase..just some leaking around spark plug hole where gauge was screwed in barely hand tight and wouldn't seal completely. What is an ok reading for this thing to run? 70? 90?

 

i'm not for sure on the lowest compression to maintain to run. mine is currently around 110 psig. maybe LT80 knows these answers.

 

My compression test was 120 but the leakdown test with piston at tdc pn the compression stroke with both valves closed was 100psi going in and 0psi being held gor s loss of 100 % because all of the air was blowing out of the intake. After a halfway lapping of the valves, the leakdown test showed a 30 % loss.. Although that's not desirable, shouldn't that be enough to run?