can I go faster

D

David Walker

New Member
G'day all, I recently lost my car drivers licence & have purchased a 80cc Motorised bike to get around on, just wondering what I can do to get it to go faster, I weigh around 80kg, have a 32t sprocket on it & getting around 35-40 Kmh , if I could get it to around 60kmh which is about 37mph I would be happy, of course I will have to get better brakes for one but is there anything else I would have to change to make it as safe as possible at this speed,

Cheers Dave
 
Get a 44T sprocket. Expect 25-30 MPH with a strong engine.. It's a hobby motor. 29 wheel - bike get a 48t. 80kg I Don't know. I weigh 155lbs.
Don't speed on a bike after losing your license.
 
Thanks for the reply Allen, I was told the least amount of teeth is a faster sprocket, is this right or is someone having a lend of me, is it possible to get these motors to do 37mph or not

Cheers Dave
 
David Walker said:
Thanks for the reply Allen, I was told the least amount of teeth is a faster sprocket, is this right or is someone having a lend of me, is it possible to get these motors to do 37mph or not

Cheers Dave
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Dave, you sacrifice torque for eventual speed with less teeth on the rear sprocket. You will want torque for hills and towing/carrying. @ 175 lbs you will appreciate a 44 on a 26" bike. Less than a 44 --- well, If you hit a 2 inch deep pothole @ 30+ mph on a bike you WILL get hurt. Speed should not be the goal. Find a happy R.P.M. where the motor does not labor/stress. Clutch IN downhill. Safety and reliability should bethe goal with your bike; and without a car to drive. Or I would think. You need to fly below the radar. Only as an example----In my world People with an O.U.I. charge operating a motor even motor assisted, without a valid license caught on a motor assisted bike will be further charged and have the bike impounded. Take the time and know your particular law concerning motor assisted bicycles. Good luck to you and I wish you safe and well.
 
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My bike is nowhere near 'stock' anymore. 66cc Skyhawk with a Fred Head, expansion chamber, tweeked carb, with a 36t on 26X1.75 Continental tires and front disc brake. This setup has been clocked at 45mph by the town's mobile radar sign. The motor is really zinging at this speed...…..wouldn't want to keep it there for very long. I may have just lucked into a great motor, but it does alright with moderate hills. It handled the hills on The Scarecrow Run just fine. (BTW, I'm around 200lbs.)

With all that being said, I tinkered with this setup for several years before I stumbled onto the 'winning formula'. Best of luck in your adventures!
 
build a custom pipe, port the engine, widen the transfers and add a third, then get a ramped windowed piston, an a reed box. toss in a high compression head and set the squish, side gap the plug, get a free flowing carb. do all that an i bet you can get almost 5 hp or more from your engine. won't last as long as a stoker, but will give you a few seasons with the right TLC. the key is to produce tht 4hp+ at around 5k to 5500 rpm, then gear to match the ability of the engine.
 
Thing is these engines make their power at fairly high rpm, so if you can never get them turning fast enough you can never go faster. There is sort of a fine line to get them up to speed and not giving away speed because they are maxed out on RPM I think that you will find that about the max you can get with a 60cc stock motor is about 30MPH. I have a 700C that does that reliably and it is really too fast to do it all the time. So some times going with a larger rear sprocket may get you a little more speed because you can get the engine up into it's best power rpm range. Larry
 
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