questions about gearing, top speed and pipe length

I have a 68cc 2 stroke bicycle engine purchased from boygofast on ebay. I am considering several different setups, but one involves changing the gearing with my current engine for higher top speed and changing my pedal gear to the fewest number of teeth possible for easier pedaling up hills. currently I have a 44t rear, and at about 27mph, my ratio calc tells me my engine is spinning at about 6250 rpm. I want to increase top speed to improve gas mileage. a shift kit is not currently an option as I have a single speed cruiser. I really like the look and feel of this bike and the way it rides. I weigh around 280. So here are my questions.

Does anyone know what is the fewest number of teeth available on a pedal gear for a single speed bike? I currently have 28 teeth on my pedal gear but would like less.

I am considering a 36t sprocket. I want to cruise at around at least 30 and get there fairly quickly, as I live in the city and there are traffic lights to deal with. From what I understand, the key to achieving speed quickly with taller gearing is the right pipe. I would be purchasing the sbp expansion chamber. What is an approximate estimation of a proper head pipe length to achieve a cruisable speed quickly?

I know that hills will be even more of an issue now than they are with my current gearing, but I believe I can overcome this obstacle by making it as easy as possible to pedal uphill. My only concern is putting extra stress on the engine, even though it will be far easier to assist the engine with a smaller pedaling gear. Will this be an issue regarding the life of the engine?

I guess by pedal gear I mean chain ring. My bad.

I have to help the motor out on hills with a 44. I am sure that a 36 will not climb hills well for me. gonna stop at the local bike shop and ask about chainrings. how about a suggested pipe length for the sbp expansion chamber?

yeah my weight is probably the main thing that keeps me from climbing hills. Im compensating for drag by making it easier to pedal. the guy at the local bike shop is retarded. he is trying to tell me the smallest chain ring I can get for a beach cruiser is 43t for a one piece crank, and 25t for a 3 piece crank. he said that the largest back gear I can get is 21t. of course, this is the guy who told me that they havent made drum brakes for bicycles in about 30 years. i dont even know why i go there. so we have hill climbing covered. how about pipe length?

sorry venice, you are mistaken. the chain ring is the gear on the pedals. larger chain ring = faster speed. smaller chain ring = easier to pedal. already went down from 44t to 28t and is easier to pedal than it was before. not sure if I will find a smaller chain ring, so I will have to get a bigger rear cog. husky sells a 22t rear cog, gonna order that eventually.

I know the top speed is going to be about the same no matter what the length of the header is. but from what I understand about expansion chamber is that a different length head pipe changes how quickly the engine can achieve peak rpm, and thats what I am looking for. I want to achieve peak rpm as quickly as possible after taking off from a dead stop, so what is a good starting point for pipe length for achieving peak rpm quickly?

actually, you sort of already answered my question. you said with a long header it had much better bottom end. I take it acceleration was much smoother and quicker with a better bottom end? so when I get the sbp expansion chamber kit, use the entire length of pipe that it comes with, and that will help out acceleration?

I may possibly get a mountain bike and do a shift kit, but we will have to see. a friend of mine just got a scooter, so maybe I can talk him into giving me his mountain bike. we shall see.

re-read the title of my post, which is, "questions about gearing, top speed, and pipe length". That means I have questions about gearing AND top speed, not gearing FOR top speed.

you have your preferred method of climbing hills, I have mine. a smaller chain ring will make it EASIER to pedal than a large chain ring.

I have a 68.5cc engine from bgf. Its not legal in my state, but I see cops all the time and they dont stop me. I am going to get an sbp expansion chamber and just experiment till I get it performing the way I want. I know now that a single speed bike is not easy to pedal up hills, no matter what pedal gear ratio you have. At least not for me. I have decided that I need to step up the game. I thought about installing a 99cc predator, but after adding up the cost of the engine and all the parts I would need, everything came to about $600. Of course, that is including a front wheel with a drum brake. I know that no matter what, I need better brakes if I want to go faster. I then realized that I can get a mountain bike at wallyworld with a front disc brake for around $200. shift kits are less expensive than they used to be, so for a little over $400, I can have a bike with a multi-speed transmission. I bet with a shift kit, the performance range is very decent. I can also control my top speed by switching gears, which is going to be safer for city driving. So I am going to go with the shift kit setup. It took me a long time to come to this decision, being that the reliability of these engines isnt all that great compared to 4 strokes, but I feel its the most economical for me.