I posted this originally on another thread, but the question requires a new topic I think.
Okay, so with the Malossi 4v head, 218 cyl and cam the performance is almost the same as it was stock. Thinking it might be a variator problem I tried WOT and achieved very nearly the same indicated top speed 120kmh. The bike (GT200) already had a LV 4road exhaust and Malossi filter.
When I picked up the bike and took it for a mid paced breaking in ride it felt lean (as it should have) with a bit of back popping on deceleration and a few flat spots. When I had a few kms on it I tried WOT and found it went better at 3/4. I upped the main jet to 100 (95 original on the Walbro carb) which sort of fixed WOT, but nothing slightly interesting in the mid range. I raised the needle by a notch and that helped fill it out, but the result is VERY similar before and after these mods. I haven't put a tach on it, though I've got one comming, but WOT at top speed should have it in the 8000rpm+ range which is enough for the setup to be doing it's thing.