Oil on piston

[SporTrax400]

I took apart my quad to replace the base gasket and put it back together and it wouldnt start, so I checked the timing about 10 times and it is right and I adjusted the valves and it still wouldnt start. So today I took it apart again and there was oil on top of the piston. Whats wrong. Also I did a compression test before I tore it apart and I only had 15psi.

What do I need to do?

Thanks
Greg

[skemp]

Sounds like there is something missing in the top end such as valve seals, or perhaps you broke a ring. Something definitely isn't right, so take it apart and check everything over. Get a new head gasket, or it will leak, throw in some valve seals, and check the rings, maybe replace them and check the cylinder wall for scoring. By all means, DO NOT try to start it any more. Something is very amiss to only have 15psi...