Mine has only done 4k miles and have had no chassis cracks just some drive train issues. I do warm the engine up first but do like to use its full potential occasionally.
I have fitted the Bleasey Centa upgrade kit to eliminate a horrible rattle I was getting which turned out to be a poorly fitting Centa to crank spline which Phil’s correctly made splined hub has sorted. It would have gone on rattling away possibly for many miles before eating the crank splines though.
Other problems I’ve had are a snapped exhaust cam, new barrels and pistons due to scoring and some work to the valve springs and seats but can’t tell you what MMC did.
So apart from the Centa splines all my problems have been with the S&S engine and only what I would call tinkering stuff with everything else.
