think the f6 will win all circumstances...the 660 isnt a sled to buy for racing or any top speed it is however a fun sled to ride and definitely is no slouch keep in mind the 660 is only a 110 hp the f6 is atleast a 120 hp
I ride my ST with an F6EFI and ZR600EFI both top out a little high, but cruising at 60--70 :cn: it really doesn't matter what sled your on. Till we stop for fuel and at 100 milles I at 1/2 and their sleds are suking the bottom of the tank. :help:
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