p0wn

I just rebuilt my xt350. It had melted the piston partially. Everything else looks good. I got the new piston and bored the cylinder out. I rebuilt it today and tried to start it. No luck. Tested compression and maxed out at 60 psi. Anybody have any ideas? My buddies think maybe it's got a stuck valve or the timing is off. We did our best to get the timing lined up but it seemed to be stretched about a half tooth off so we couldn't get it perfectly lined up on top dead center. We went with a half tooth advanced. Anybody have any ideas on this? Thanks