12,500 or 13,000 rev limit (2 models)
does away with secondary throttle valves and electronics
no 6th gear speed limiter
Peter D Motorsports in Phoenix can get them. Car guys, but Yosh kit part enabled.
2005 Book of Speed (Yosh printed catalogue) has kit parts (did not admit there was such a thing in years gone by). Maybe you can even get Yosh kit parts from Yosh now.
keep in mind its only useless if your going to build the motor just b/c the rev limiter is increase to 13000 dont expect your bike to be faster.... you should change the springs and use diff cotters to avoid valve float once you have internal work done...