I have a 98 RMX250 and have the oppurtunity to get a FMF fatty exhaust and muffler off a 97 RM250. How much better would this make my RMX go?? Any other changes needed? eg jetting etc
I'm not much help on much re: non US RMXes, but do know they had different sized exhaust ports from the RM beginning in '91 on up. Non-US '99-up RMXes shared frames and other parts with the '96-'98 RMs.
If it fits, that setup would certainly make a difference. FMF used to offer some generic jetting specs on their web site.