Personally I think the '18 is a better motor, internaly it is much closer to an RS than the '21 is. However the '21 does have a better cylinder design (cooling wise) but not porting.

Heres my '18 running race pipes, and air box mod vs my old '21 with race pipes, HRC jet kit, open carbs with HRC loom and delimter box. The '18 feels so much faster though it has alot less mods. The F3 '21 kicks the '18 to hell but thats not really fair.


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If I have to take the carbs off once more...