01 bottom end catastrophic failure

[norby449]

My 01 rappy just gave up the bottom end, The key that holds the drive gear broke, and it spun on the shaft. It wiped out everything. All the gears are missing teeth,the clutch basket is in many pieces, The outer case is cracked. The rod took a big hit from the balancer witch is also broken I'm sure I need a new crank. I can't understand why this would happen. I have always maintained this quad above what is normal and the oil was only 15 minutes old when this happened. Anyone else ever seen this? Got a reason? All this because Yamaha did not want to spline a shaft. I wonder if cryo treatment to all the keys would be a good Idea?

[Krandall]

If this is the first time it's happend. I'd consider yourself lucky it's made it the 8 years it did.. The 01' 660's were notorious for having transmission issues taking out the bottom end w/ it.

[Peelz]

Just upgrading to post 2001 Tranny gears fixes it. They sell a kit for it too. $400 I think.