I remember reading a dirtwheels(a late 80's issue), the 86 tecate 3 and the quadzilla were the fastest at nearly 85 mph, 86 atc250r was at almost 80(trx was close). Really, the fastest atv ever produced in a tiger 500 three wheeler(limited number, usa built), dirtwheels had it to almost 90 and it still had more to go. They said that it had enough power pull 2 tooth bigger front sprocket too. Tiger didn't produce too much of them, as with the 80(lowest number), 125(very rare), 200(rare), 250(most common), and 500(very rare, few still around).

I don't know how these compare to the current atv's, atc250r's and tecate 3's are still blowing away current quads. I have to agree, top speed isn't too important. Get up and go is more important, I can't think of too many places except dunes and drag strips where you can open up atv's.