A friend of mine had the MC28 and it really was a brilliant bit of engineering but was limited to 40 HP. The full-power card really was only for the track so the lights and indicators wouldn't work and a new wiring harness had to be made or bought in from Japan. IIRC there was a similar spec RGV 250 import that needed similar mods to run full-power.
I have had a lot of bikes over the years but the 2-strokes really do bring back fond memories as they were very involving in keeping them on the road and made such a great zing-zing sound. Let me think: KX80, MTX50, FS1E, AR80, MTX125, KMX125, RG250 Mk2, NSR250 and probably a few I've forgotten. The KMX was a brilliant bike, even got it clocked by the police at 90mph on the motorway, only got a bollocking cause they couldn't believe it went that fast Had a modified exhaust and the KIPS valves turned but that was it. Used it for trail riding and even managed to fill the gearbox with water on a river crossing and it just carried on!