Sheered woodruff key!!

So today I was riding along at moderate throttle, coming up to a steep hill I went wide open to keep my speed up. With my properly tuned RT carb, new piston rings, and home made expansion pipe it has some serious awesome torque.
So as I throttle up, the engine just revvs waaay up, and I started slowing down.
I came to a complete stop, clutch engaged, engine idling... That's no good!!
I assumed the clutch died, so I pulled out my screwdriver to take the clutch cover off thinking I could adjust it, but nope, when I rolled the bike the disc in the middle wasn't turning. Hitch hiked home, and came to pick up the MB with my car. When I got it apart, sure enough, the key on the drive sprocket had sheered clean in half.

A trip to the hardware store I got a key that was a bit too wide, and way too large. I used the grinder to get it to size, and I'm on the road again.

But what a weird break down!! Anyone else ever had that happen?

Chain rivet! That's a great idea!

247Jude said:

Thanks that is what I need to try, I have been sheer keys left and right side of the motor. I too upped the torque of my two stroker and have been sheering keys left and right so quick I only get down the street. I changed my head to a high compression slant head, the chamber is about half the size of the original.

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If you're sheering them off that fast, you're probably using keys that are too thin and/or two small. If they're too thin when you go from decel or starting to accelerating, the sprocket will spin to the other side of the key, that's a lock of shock loading. And it will sheer the key in half. Also, if it's too short, it won't have as much to grab on, a combination of this will sheer them off pretty easily.
The one that's been in there is the original one with thousands of miles on it, so it was bound to die eventually...