cgallant

The cylinder walls and head are in good condition no signs on the walls. As well as spark plug, checked the bearings look fine no play. no any foreign materials inside, note that the bike was running but difficult to start and hold idle. so i believe all it needs is a piston rings.

What about the blackness under the piston rings? is that an indication of blow by from the chamber? meaning was loss of compression?

You have also mention that i should replace the piston as well do you think i should?

thanks