Really, all the parts between the 21-28 are about the same except things the frame, swingarm and electricle system. But if you want to change from mc21r forks to mc 28sp forks, then you will need the brakes as well. The clutchs should change from and R to SP with no problem, as long as you have all the parts.
Your questions should be more specific.
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
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