Kitty Cat Snowmobiles

i finally got around to do my crank seals on my kawasaki 60cc kittty cat engine and i found out some more problems. the pto side crank bearing let go which put metal into the crank case inturn scoring the piston and cylinder. does anybody know if i can get a crank bearing and an oversize piston. i also looked at the parts breakdown for the engine and i noticed they show crank shims but my engine did not have any does this mean somebody was in there or was it machined right fromt the factory and did not need shims. my machine was produced in aug 1972 does that mean it is a 1973 or a 1972. if anybody could help i would greatly appricate it

I HAVE SOME NEW AND USED BEARING FOR THE KAWY'S. HOW BAD OF SCORING DO YOU HAVE? OVERSIZED PISTON ARE VERY HARD TO FIND IN AT ALL. THE SHIMS ARE JUST THERE TO AJUST THE SIDE PLAY IT MIGHT HAVE EVER HAD ANY. IF IT'S A AUG 1972 IT'S MUST LIKELY A 1973.