[EricH]

I wouldn't put the blame on the dual CIMs. Teams have been using that setup for years with few problems. (254, you want to chime in here?)

I'd look at your sprocket alignment first. #25 chain is quite finicky about how it's aligned--get it off by too much, and you'll have problems. Hit it right, and you'll work for quite a while with no problems.

Then, I'd look at your chain tension. Are you really loose or really tight? Either one could cause trouble. (It could also be that you had a bad batch of chain.)

And, if all else fails... #35 chain. It's more tolerant of misalignment, and tougher than #25 to some extent. But it's also heavier. You could probably use it on the "weak" link and that should solve the problems.

Like I said, I don't think it's the 2-CIM setup, or inherently a problem with the #25. I think it's alignment or tension that's causing the issue.