Makeing old kx into race bike.

[Krossipoiss]

Hey.I'm planning to make my old 1987 kx125 into a race bike(To get top5 in local B-class)

Already done in engine:
Boyesen pro series reeds.
Pro circuit exhaust.
12-47 gearing.
Ported cylinder.
Some aftermarket clutch
Twinair air filter.

Already done in frame:
Renthal handlebar.
Smith soft grips.
Grip seat cover.
New front brake from kx250 2002 or 2003...

*What to do more in frame?
*What to do more in engine?
Is it possible to put on some newer bike suspension?Does some older kx125 USD front forks fit(smth like 93clamps to 87 frame?)
The rear suspension..Is it possible to put on new suspension swing and newer shock?

 

[_JOE_]

I would sell it and buy a newer bike before I'd attempt to fit different suspension. Just have the stock stuff rebuilt/set up and you will likely be the only thing holding it back. Just keep in mind it's going to be at a disadvantage against more modern bikes.