Picked up '97 CR125. Piston and rings questions.

Ok, compression is almost nonexistent and the plan is to put new rings and maybe a piston in. We've removed the head to take a look inside. How do we know what exactly we need to order? We are rookies at this, but have mechanical skills. 

Don't order any parts until the cylinder has been inspected (damage, worn plating etc.)

Any scratches or gouges that can be felt when dragging a fingernail across it ?


If the cylinder if still serviceable, you must then measure the bore to know which piston size to order.


Check for connecting rod up/down play.

With such an old engine, don't take chances and replace both crankshaft seals.

Edited by mlatour

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