Re: Predator 670cc V Twin bike
Lower cc, but double the rpm. That V-twin is an industrial engine, not a motorcycle engine. It doesn't have a transmission, and you can't afford the Harley big twin transmission that you might be able to cobble up to work with it. About the only other option would be a CVT, which is about $300 in a size that will work with that engine. And a CVT wastes a lot of power.
The Piranha 140 makes about 12 hp, but it is much lighter and has a manual clutch and 4 speed transmission built in. I don't even have the 140; mine is a 125 with the small valve head (the 140 has a big valve head). My 125 only does about 8 hp, and I have it geared low for offroad use. But it will still do 55 mph on the highway. So yeah, a 140 with a sprocket chosen for road use will definitely do highway speeds.