How to improve 50cc acceleration? By turtle8 (Read 4,311 times)

[turtle8]

Hello all,

It has been ages since I've been here. I just finished working on a friend's 50cc SMM V-Sport scooter. His fuel systems was all messed up due to crappy fuel lines. I dismantled the sealed carb, cleaned and installed new screws (to replaced the drilled out screws). I also installed a new fuel filter and clear lines. The scooter was also experiencing a loss of power. A valve adjustment fixed that. What can be done to improve the acceleration? The scooter has just over 1,000 miles on the odometer.

[cyborg]

Some if not all 50's have a restrictor collar between the variation halves to restrict top end ,,, also they have an exhaust restrict or washer in the exhaust right by the head,,, pull the two nuts for the exhaust you'll see it in the pipe,,, also some have a block in the throttle housing so you can't go wide open and some have one by the carb linkage where the throttle cable hooks up to the carb

[fufsgfen]

After restrictions are 'fixed', then something of these might help further.

Replace rollers with lighter/heavier, idea is to keep engine at max power rpm during acceleration, sometimes stock rollers are bit too heavy, sometimes kids will put 5 gram rollers because internet said it will accelerate faster, but that might cause only more engine noise and shorter engine life.

There is no acceleration to be gained by over revving the engine, so making sure engine stays within powerband is aim when changing weight of rollers.

You can also change different variator unit and rear variator pulley to unit where there are different shaped grooves, changes might help to keep rpm at maximum power rpm, but cost of that is that at cruising speeds rpm stays also at maximum power rpm. However with 50cc there might be reason to do such change.

With big bore kits, standard parts give best acceleration from my experience as there is torque to make scooter move, so most of variator performance parts seem to help most with 50cc.

Best bang for buck was big bore kit, hands down, we did one for friend's scooter and it took 3 hours, some will do it much faster, but for the cost of 40 euros and 3 hours of time, performance increase was a lots, hardly need to use more than 1/2 throttle, with heavier rollers getting started up on a slope became very easy and no screaming engine, just low growl and rapid acceleration, of course not quite legal, but for sensible adult driving that made scooter to work like it should.


Best performance upgrade I got was when I lost 40 pounds of my own weight, but that might not be option here.