Beta Riders Club Discussion Forum

Installed a FMF Factory Fatty and the o-rings are barely squished in the exhaust flange. The FMF o-rings had zero squish. Anybody else have this issue?

So FMF jacked their measurements. Fitment is around 1mm smaller OD. Purchased a new stock pipe, and exhaust flange, to measure. If you want an FMF pipe, use liberal amounts of RTV, or save the fitting off the stock pipe to weld on new pipes. I have only compared to FMF Factory Fatty.

would expect more from FMF, glad you figured it out.
is FMF to todo their design?

I don’t know, haven’t purchased another for 4 months so maybe they already fixed?

Odd, my Fatty for 21 XTrainer fit perfectly. Same engine as 21 RR so you think they would have kept the same manifold part. . . Unless the change to the 22 engine made for a smaller outlet, And they didn't change?