Honda Spree and Elite 50 Forums

Can someone please give me some insight on this issue I'm having.
I have an 86 Spree with low compression 30lbs. It would not start. I pulled the cylinder to find a broken piston, scored cylinder wall and what looks like a base gasket leak. There is plenty of oil and greasy grime everywhere.
I had an extra, used piston, rings and cylinder, all from extra parts box. Everything looked clean and fit really goid together, I thought they fit like a glove. I put brand new top and bottom gaskets on the head and cylinder. Once it was all back together it barely started and my compression only went up to 40lbs.
Do I need to look for a crack in block or something else.
I put 7lbs torque on the head bolts.
Thanks for any help.

Torque those head bolts to 10 lbs and retry. I know book says less but 10 is safe and sure to seal.

Greetings:

Cracks will show up as dirty lines wherever they are. Seals at the crank ends need to be sound. Reeds must be installed but the carb removed or held wide-open while you crank up compression. Add a few drops of 2-stroke oil and re-test. If compression goes up significantly, the ring fit in the cylinder isn't right.

Solid advice!

Ok, thanks for all the advice. I'll let you all know what happens.