Hello everyone,
I'm tearing into the engine on my lt230. After finding out the wrist pin came off the piston and sent half of the piston into the case I turned to the spare engine and parts I have. No clue on the condition of the spare engine I took off the jug. The sleve is clean but the piston is grooved up. My question is, the markings on the piston say art on the side and on top its marked 0.5 Does that mean it is not 66mm stock bore and piston. In the box of parts I have a new wiseco piston that is 66mm bit I'm afraid it will be to small. Any feedback will help.

 

The 0.5 means it's 1/2 a mm larger than the stock bore.

 

Stock bore is 66 mm. Your spare cylinder had a piston that is 66.5mm. Your Wiseco piston (66mm) is to small for the spare cylinder (66.5mm).