More Power!!!!!

Discussion in 'Motorized Bicycle General Discussion' started by Bigredgasbike, Apr 13, 2010.

  1. Bigredgasbike

    Bigredgasbike New Member

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    I have a 48cc engine on my gasbike and i live on the top of a huge hill, which it has a little trouble getting up (i have to pedal with it). Is there any way i can give it more power, without changing the displacement? (48cc) I haven't tried anything yet (if there is anything) so im open to suggestions.drn2
     
  2. ZRTMWA

    ZRTMWA New Member

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    New exhaust (expansion chamber) and a nice spark plug will both give it more low end power. A sprocket with a higher amount of teeth will help too but your top speed will drop. If you really want to shell out the big bucks you could get a SickBikeParts Shifter Kit.
     
  3. Bigredgasbike

    Bigredgasbike New Member

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    Im not sure weather i want more low end power or more speed overall, is there any way i could speed it up without replacing the sprocket or changing the 48cc displacement?
     
  4. mapbike

    mapbike Active Member

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    Speeding it up will make it struggle even more on the hills, how many teeth does your final drive srocket have?
     
  5. crobo

    crobo New Member

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    expansion chamber will give ya some good performance.

    gasket and port matching will improve flow and give ya smoother and slightly higher performance.

    i live on a big hill to and i changed my plug and wire recently and its def helped in the lowend.

    also make sure your wheels and tires are in good condition, i recently got rid of my knobbys and replaced my wheel bearings and the difference is night and day.
     
  6. Bigredgasbike

    Bigredgasbike New Member

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    i dont know let me check... i counted 44 teeth
     
    #6 Bigredgasbike, Apr 13, 2010
    Last edited: Apr 13, 2010
  7. crobo

    crobo New Member

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    i have the same sprocket size, im 230+ lbs and my bike had trouble before i did what i mentioned above. now it makes it up going what im guessing is close to 15mph no pedaling.

    try the stuff out that i said, get some gasket paper (5 bucks) and cut them to match the port on the engine, if you have a dremel check out this thread: http://motorbicycling.com/f13/basic-porting-time-fer-teh-lolz-16646.html

    the plug and wire are available from SBP, <20 bucks shipped and it is a very noticeable difference
    plug: Sick Bike Parts
    wire: Sick Bike Parts

    any local bike shop will be able to repack/replace your bearings, usually for around 10 bucks. and im not sure what tires you have on there but anything smooth will work nicely. and new ones will cost you around (30 bucks)

    also, grease the gears inside the clutch cover lightly and make sure your chain is lubed well. any auto grease will be better than nothing (5 bucks)

    everything ive described will make it a brand new bike and all for ~70 bucks (30 if your wheels are in good order) that motor with that sprocket should def be able to move you up a hill when its cleaned up
     
  8. Bigredgasbike

    Bigredgasbike New Member

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    ill try that thanks!
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I would make sure the engine is broken in fully and the carb is set right before spending money.
     
  10. Randog707

    Randog707 New Member

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    Break in engine first,and if you cant take that hill,buy a 56 tooth sprocket and you"ll reach the top no problem,but you will lose some top end speed
     
  11. city of angels

    city of angels New Member

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    i will recomend a expasion chamber i rode in a bike from usa bike motors.com that the expasion chamber and u could feel the difference on speed and acceleration they dont have them posted on their website u have to call for price
     
  12. Technocyclist

    Technocyclist Motorized Bicycle Senior Technologist

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    Dual tailpipe mod...

    If you can't afford an expansion chamber then try the "dual tailpipe" mod. Drill a 10mm hole beside the existing tailpipe, then insert a 3/4 brass male coupling. You have to rebore/redrill the male coupling to have a 8mm inner diameter. The maximum tailpipe diameter should be 16mm based on the exhaust port dimensions. Existing tailpipe is only 8mm, but you can measure it just to be sure as long as the total is not greater than 16mm. Set the male coupling with some muffler glue if you don't have a welder. However, this causes your engine to run lean so you have to adjust your mixture and/or your carb to run richer. I think this mod only works on mufflers that has a bolt in the middle - the one that has no cat. (meowwww !!!) :) Check your plug afterwards and engine temp.
     

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