TZR250-the reverse cylinder one, they could be mental fast with a few TZ250 bits.
Suzuki GT500-superb big stroker, bloody strong engine too.
Kawasaki KH500/KH750-you want mental?you got mental!
Honda NSR250 MC28
Suzuki RG500-with Stan Stephens stage 3 of course.
Notice anything strange yet-like my choices are all strokers...........
John