Originally Posted by ZnsaneRyder
If you want more top speed from a taller gearing, then you will have to pedal more to take off regardless of engine size. That's the great thing about a bicycle. Pedal-Assist along with the engine during takeoff, up to about 10-15mph, then the engine will take over from there.
The "80cc" 2-stroke bike kits have plenty of power for 30mph. Go smaller than the average 44 tooth kit sprocket, and you will be going even faster. I rode with folks in St Pete and ALL the 80cc motors did over 30mph.
Your are only 250lbs, that's not very heavy for a good motor. Even my bro's 80cc 4-stroke 2.5HP motor can haul my bro's 300+lb friend to 30mph, it just takes a little while.
Not really legal, BUT, you could go with a 6.5HP, 196cc 4-stroke Lifan (Honda GX200 Clone Engine) from Harbor Freight Tools if it fits on your bike. Remove all HP and CC stickers. It's a big and heavy engine, so I don't know if it fits your bike. I have one of those engines on my pusher-trailer and it gets me 50mph with ease. However, with my tall gearing for speed, I still pedal to takeoff from a dead stop, to save the life of my centrifugal clutch and to make it easier on the engine. If you had one of these big motors, and geared it to go only 30-35mph, it would have excellent takeoff.
i just checked harbor freight,they have the engine you mentioning for 160 dollars,to me thats a steal for a 4 cycle from what ive seen everywhere else. but im looking at it and i think the pull start is in the way of the chain.looks like id have to make a motor mount to bring the whole engine out of the frame some and then use a jackshaft to get the gears to line up.damn shame on those centrifugal clutches, i know how they burn thru shoes on mini bikes. a sweet set up for that would be like the primary and secondary centrifugal clutch on a snowmobile.in a set up like that,the more rpm's the closer the plates get causing a different gear ratio,so it would be like an auto trans.lol now im off to see whats the smallest one of those i can find or engineer!
edit-- i think im looking at a arctic cat kitty cat engine for reference