Hi!
I have a problem with my Honda GX390 that I got for free from my grandpa because it needed new pistonrings. Now I've replaced the piston and pistonrings but there is a looot of friction when turning over the engine and it only has 70 psi compression. I've set the valve gap to 6 thou intake and 8 thou exhaust. Headgasket is also new. Bearings feel good and spin freely
What could cause this?

 

Did you check piston ring end gap when you installed them? I assume you properly honed the cylinder and there were no bad spots or gouges?

 

Did not hone since the crosshatch pattern looked good. End gap was .4mm as recommended in the shop manual.

 

The crosshatch pattern is worn down and smooth now, it won't seat in your new parts. It's broken in to the old rings.

 

As I said, the honing pattern looked good, maybe it was honed before I got it. But yeah I could hone it again just to make sure.