Does anybody know if you could use a cdi off of a 90, to replace one for a 50 and still have the limiter? (if you want to use the limiter)
If it would work, would there be any performance gains?

 

I believe the 90s and 50s have the same cdi. Theres no reason to have the limiter unless it's to slow the bike down. We race the 90s and 50s and wring the heck out of those motors turning many more rpm than stock and they hold together, same with the suzuki lt80.