last month we had almost 6 inches of snow and wile plowing the drive the engine stopped. tore down and piston cold siezed on the exhaust side. i knew this engine needed a bore from last time the crank seal went bad and piston burnt. i just cleaned it up and put in a standard piston and drove the bike this way for two years plowing and beating on this thing with no issues until just last month.

so, now it has a .040" bore and wiseco piston. ran about half a tank of gas through it and today had issues. was plowing some stones and the engine was making some knocking noises just like when it siezed last month and stopped running. sounded really bad, metal on metal type scraping. got it towed up to the garage and was lookin it over. decided to pull the cord and had good compression. hit the key and started right up and ran fine. sounds perfect. 40*F today

wondering what the heack happened. anyone got any input.....

 

Did rod have ANY vertical movement (side to side ok) when you did top end? Plus has bottom end ever been looked into? If original bottom end could possibly be problem. I have had a few "takeout" bore jobs I've done that customers should have addressed bottom end also. This can take out a new top end and lead to double work. Just a thought. opt