My 98 powder special 600efi has just spun the threaded stub end off of the flywheel side of the engine. Stopped on the trail and when I hit the gas to go it backfired and quit. After some searching and pulling off the recoil, the flywheel fell out. The woodruff key had sheared itself and then twisted the threads off. This is the second crank in this thing because last year I had to put a new one in after the original split in half. When that happened it wrecked one of the cyls. So that was a pricey fix. Earlier this year one of the piston pin needle bearings shattered and took out the other cyl. I am very much considering giving up the sport I love because I cannot afford to keep putting this much money into a hobby!! I have only had one sled that never blew up and cost me a small fortune and that was a 95zrt 800, and that is out of 7 sleds!