Join Date: Dec 2009
Location: Black Mountains, N.C.
660 Stock Horsepower
I have a stock '07 660.
I found a few different performance sites that mention the HP. One said they put a stock 660 on a dyno and it came up 24 HP. Another site that sells K & N air filters claims that the 660 is about 31 HP stock, and adding their K & N filter will add around 4 more HP. I can't find any mention of HP in any of the Yamaha specs I've looked at, they list pretty much everything but HP.
Is there a generally agreed upon HP rating for the 660 engines? I'm guessing every year from '04 forward is about the same?