TZR 250 KX500 Roadracer

[Roadracer]

I have a TZR250 frame and a complete set of TZ250 suspension components that is just dying for an engine. I found an 86 KX500 for cheap and would like feedback on the level of stupidity involved or required to make this work. Is this the wrong year or can it be updated to later crank and ign? How fast do you think it would go(fulll race fairings)?

[dave916]

I personal would not bother with the 86 kx motor, too many part now getting hard to get , 86 also looks like it has the mildest port timing compared to later motors
It is going to be no advantage to get later crank and ign?
A TZR motor will put out more hp than the kx without any vibrations or surging issues
alot of work for very little return

Here in the UK u could buy a complete tzr for less than  the price of a kx motor

good luck if you are going to do it but u would be bettter getting a 89on motor