How fast can your 49cc Really go?

Discussion in 'High Performance Bicycle Engine Tips and Motorized' started by stv1jzgte, Feb 22, 2009.

  1. stv1jzgte

    stv1jzgte New Member

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    I have seen the 67cc(80cc) speed from 25-50mph but how fast have you gotten your 49cc bike to?
    with a lil tweeking ive gotten up to 47kmh 30mph on flat ground!
     
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I have not ridden mine enough to break it in yet (winter) but so far it goes 25 mph no problem. I am believeing it will go just as fast as the 70cc kits, they just have a little more torque.
     
  3. Etacovda

    Etacovda New Member

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    i had mine at 47km without any tweaking.
     
  4. cnico

    cnico New Member

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    my 48cc will sit on 55km/h on the flat but with a little tail wind it will sit on 60km/h, top speed down a moderate hill has been 68km/h
    only mods that i have done is matched the inlet and exhaust manifolds to the ports removing any burs, leaned of the carby as the stock carby is the same for both 66cc and 48cc (much to rich for the 48cc), fitted an expansion chamber off a 48cc pocket bike and changed the rear sprocket from the stock 44 tooth down to a 28 tooth :)
     
  5. stv1jzgte

    stv1jzgte New Member

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    51.0kmh now! haha
     
  6. Creative Engineering

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    I'll say 52-58 MPH installed in the right bike...engine slightly prepped...no billet replacement parts, just machine work on the existing parts...and a light weight rider, (160 or less), with a shorty plexi fairing.

    Jim
     
  7. stv1jzgte

    stv1jzgte New Member

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    Not a pipe dream thread! How fast can your 49cc really go? Maufacture says.... 30-35kmh 21.7mph
     
  8. stv1jzgte

    stv1jzgte New Member

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    As im sure you know its dam near impossible it incress torque without incressing power.
    Every distributor that ive seen that sells these kits in Australia and the States, power figures are always higher for the 80cc70cc whateva so of course Torque will be a little more!

    Do the same mods to a 49cc and an 80cc i guarantee you the 80 will have a higher top speed!

    steve
     
  9. Creative Engineering

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    Moderate machine work will make a world of difference in the perfomance!

    50+ MPH is easily doable if you have the balls to ride it!...My race car engine customers ask me all the time "what about this", "what about that", I tell them sure...just hang on...it's going to be a ride!!!

    Jim
     
  10. Dave31

    Dave31 Moderator
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    Yes, but we are speaking of motors with no mod.
     
  11. stv1jzgte

    stv1jzgte New Member

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    I do understand what your saying and i have the nuts to do 50mph no worries! I have a Toyota Cressida i built that does 12.1 @112mph my mates
    10.9 @128mph and everyone said its impossible for std ceramic turbos to see 28psi. its a fun ride
     
  12. stv1jzgte

    stv1jzgte New Member

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    What?
    49cc and 80cc the same ie 2 std or 2 with the same mods
    i know that the 49cc will rev harder that the 80 but put a 36 tooth gear on a std 49cc and no way in **** will it go as fast as a std 80 with the same gear
     
  13. Dave31

    Dave31 Moderator
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    I have ridden the 48cc, 66cc,& 70cc all with 44t sprocket...top speed has always been the same.
     
  14. stv1jzgte

    stv1jzgte New Member

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    Your right the 44 tooth is the exception only because its within the 48cc power range and it can reach top rpm.
    on that note you could assume that the 48cc could be faster with the 44tooth because it revs higher but all falls away once a smaller gear is used.
     
  15. thatsdax

    thatsdax Member

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    Typical top speed for the F50 and F80 kits that I sell are around 28-32 mph top speed with the 44T and 26 inch wheel. Higher speeds, much higher with the 36T. Near 40mph .. This is with a stock motor and keep in mind, I am 6000-9000 feet high.. Enjoy the ride...
     
  16. stv1jzgte

    stv1jzgte New Member

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    I can get a F50 Type in australia amoung others, the seller has stated to me that the F50 will not pull the 36tooth sprocket as well as an F80 will.
    Do you modify your kits before sale?

    [​IMG]
     
  17. Prasinos

    Prasinos New Member

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    my 50cc clocked 34 and 35 going back and forth on a strait away. upgraded intake air filter ignition and 36 tooth sprocket
     
    #17 Prasinos, Mar 11, 2009
    Last edited: Mar 24, 2009
  18. impression

    impression New Member

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    ok, lets put a stop to the whole 'they all go as fast as eachother' BS.

    in a perfect vaccume sealed environment the engines will both reach max rpm right ?

    but once you factor in outside influences such as gravity/wind resistance/rolling resistance/wheel diameter/sprocket size each one of these has a factor upon the top end speed.


    so, all things being equal lets say a 44t sprocket, on the flat. But you encounter a 5mph wind resistance upon the same person with say 1m^2 surface area while riding. The smaller capacity engine will not get the same top end as the larger engine as it would not have the raw torque/power to pull through the wind resistance.

    conclusion: both engines will rev to the same rpm, pull the same tooth sprocket, but once resistance is found in one place or another the larger capacity engine has an easier time dealing with it.

    EDIT: trying to find a 36t or smaller sprocket in Australia, any ideas :(
     
  19. oylavabeer

    oylavabeer New Member

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    I have 2 x mountain bikes one 50cc one 66cc with similar milage I weigh 100kg and would choose the 50 for any speed over 15kmh and it gets to top speed quicker even up hills ( i call him Herbie )dnut
     
  20. saetta

    saetta New Member

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    My 49cc Chinese engine is out of box stock. I drilled additional air holes in the black air breather. Mounted on my 26" single speed cruiser it will go 29 MPH on a flat street.
     

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