I have an opportunity to obtain a 2007 400 AC four wheel drive with automatic and belt drive. The problem is this bike has been blown up...after it began smoking it was continually ridden rather than re-ringed and eventually it lost all compression and smashed the end of the spark plug flat!
I would really like to get this bike and fix it but I have doubts about the motor (is it a suzuki) and if the case will have to be split. The motor isn't locked up, will turn over freely, and I can do a ring and piston easy.
Anyway...any tips, pros or cons on these bikes will be appreciated.

 

If the piston "kissed" the spark plug then you may have more problems that just needing a new piston and rings. It's possible the the lower rod bearing may have gone out. Or it could just could be part of the rings/piston debris on top of the piston that damaged the plug? Only way to know for sure is to tear the head and cylinder down.If you're going that far I would lap the valves and install new valve guide seals also. I've bored a few cylinders for older Arctic Cats that customers brought in. I think the engines were Suzuki supplied. OPT