Bonneville America Forums Forums Technical Forums General Tech Sprag Clutch shot!!!!

On a ride last week my bike (03 America) started to make some horrible crunching type noises when attempting to start. Pulled her apart today and found the spring that goes around the sprag clutch lobes had disintegrated, chewing the sh!t out of the lobes and the housing. No biggy really, just need a new part and alls good. BUT.... I believe this to have been caused but the occasional backfire that we some times get on startup. The castings for the starter Idler gear seem fine but I am gunna crack test that area before I put it all back together.
I also noticed that if I grab the outside of the clutch basket and give it a wiggle there is a bit of movement there Right through the whole clutch assembly. Any one have any Ideas whether this is normal or should I look into this further while I have it apart????

First time I've heard of a sprag clutch failing. Glad it's repairable.

Glad to see you are taking a close look at the idler gear bushings. If I ever get around to taking my clutch cover off, I intend to try to place/press/force a steel bushing over the cast ones. I'd pack everything in plastic steel epoxy to try to reinforce the area. The trick is to get around to doing it....

I don't think a steel sleeve over the sockets will do much from what I have seen of the failure. Would need to weld gussets to make it like the new style casting so the force is spread out more on top the rest of the surrounding cases. Or build up all around it with weld. In any case not sure it could be done with out engine disassembly due to the heat required and oil contamination of the welded area.

Does anyone have pics of the old and new castings?

No pic but the old case has just a round boss for the starter gear to ride in and the new has webs on it to disperse the force.

Outwardly the old case has the breather tube off the back of the cyl. area kind of behind the primary. There is a square area off the back of the top of the primary that protrudes under the carbs. The old case is more or less flat there.