do they accelerate fast(the 400 and 500)... or do they accelerate like 2 seconds after u pin the throttle and if they do that still do they accelerate fast or are they slow

 

I wished I would have spent the extra $ from the first time I rode my '01 SP400. After clutch, jets, filter, & belt upgrade, the 500HOs would still outrun me.

Stock, they accelerate immediately with throttle. They pull hard most of the way up. At about 45 mine would slowly accelerate to 52 (top speed).