I broke a chain last week!! At the same time my drive sprocket sheared off of the drive pinion. I'm not sure what happened first...but it looks like the chain slammed the drive spocket into the swing arm: cause it took a bite out of it!!

The good news is the damage was minor ('cosmetic' chip on the cranckcase cover corner, teeth marks on the swing arm, sheared sprocket retaining ring, and a mashed lower slider). I've since replaced all the damaged parts, necessary, and have a new D.I.D. chain on the bike.

My concern is: will this happen again. It just so happened that I had tightened the chain, just before the ride...and it broke within 15 miles . I'm not sure how old the chain was, but it could have looked better. At the same time, I may have gone a little tight: with ~ 0.8'' deflection and no one on the bike. Alternatively, I am also wondering if I may have misaligned the chain, due to the nature of the failure (although I've read posts stating this was impossible).

I'm thinking about taking it out for a ride tomorrow, but was hoping I would get a red flag from someone, if it looked like I could use it. The current chain has 1'' deflection with a passenger on board, and 1.2'' without. As far as I can tell, it looks fine to me...but I am one step away from clueless!!

Here's to a nice ride tomorrow

Michael

Your present adjustment should be OK, but remember it's always safer to have a slightly loose chain than a slightly tight one.

Glad to hear it Skins!! I will keep that well in mind. The last thing I want to see is one less Paso on the road!!

Michael

Sounds like the sprocket retaining ring came undone. Use some threadlock compound for those tiny allen bolts. The sprocket wouldn't normally come adrift because of a broken chain but the chain could break because of being hindered by a jammed sprocket.

you`re lucky the engine case is ok.
http://www.desmotimes.com/product70.htm

G.

paso750 - yeah, I know....very lucky. I think I will invest in the case protector. Thanks.

JWilliam - Actually, the bolts were locked down tight. It was the retaining ring groove tabs that had sheared away! I am not sure what the root cause would be for this, but I am learning as much as I can about this type of failure.

Easy riding!