1988 lt230s help!
Hi everyone, I recently rebuilt the top end engine of this atv. I went oversized on the piston by 1.0. Everything is correct timing and all that. My issue is every time I kick start it excessive pressure builds up and escapes through the oil filter cap housing. I have gone through 3 oil filter caps because the excessive built up pressure cracks the caps and sprays oil every where. and the crankcase breather system is unobstructed as well. Any ideas on what is causing this excessive pressure?