motor problems

[OnTheEdge]

I bought a 87 250x with the typical transmission failure. Compression was at 200 psi before teardown. Tore it apart and fixed the transmission then put it back together and now have little to no compression. I did put all new gaskets in also. So, I pulled the top end off back off and the rings were good, didnt bend or break. Check compression again without the head cover on so that the valves were not opening or closing and I still have no compression. I put the compression gauge on another quad to make sure it does work, and it does. It has a wiseco 12:1 piston in it and I might have put that in backwards. That is the only thing I can think of. Please anyone chime in if they know something that I might be missing.
Thanks, Nic

[John451]

Yeah, sounds like it's backwards or the valves are adjusted wrong. does it have a decompression lever? make sure that's off. good Luck!

[OnTheEdge]

I had the head cover with rockers off, when I checked it, therefore it can not be valve adjustment. I contacted Wiseco and the piston is in correctly. I can only think that maybe a valve got somehow bent. Decompression is disengaged/disconnected.

[John451]

Did you get new rings with the piston? Did you get the right bore piston? Did you get your cylinder bored or honed bofore getting the piston? Alot of the time people will get the piston then get it bored but get the piston for how it was before.