So I have a 300 Xplorer that I’m working on for a buddy. So I recently removed the top end and sent it along with a new namura piston and the cylinder to get bored .020 at a machine shop (reputable shop)I put it all back together and I’m only getting 100psi. What did I do wrong? I checked ring end gap and it was .010 to .012. Thanks for any help

compression raised to 110 when I put a little oil in spark plug hole and tested

 

Bump

 

Edit: wow, not sure how this post made it into this thread instead of my original one. Sorry for the error.