centrifugal clutch and pull start kit , plz help

Discussion in '2-Stroke Engines' started by shaddy, Jan 21, 2014.

  1. shaddy

    shaddy New Member

    hi guys
    i wanna install a cent clutch and pull start on my motorized bicycle but i have some questions
    1- is it have enough torque to run from the rest like cars and motorcycle or must pedal first
    2- http://www.instructables.com/id/Motorized-Bicycle-Centrifugal-Clutch-Install/

    from the link above i see that the old clutch cable still installed , why ?
    3- is it have smooth ride on low speed under 15 km/h ?
    4- what about this kit is it work fine

    plz help

  2. wheelbender6

    wheelbender6 Well-Known Member

    Shaddy - I still had to pedal away from stops after installing the centrifugal clutch. However, I really enjoyed riding more with the cent clutch.
    -The original clutch cable remains for maintenance. You may need to rotate the rear shaft without load during maintenance. The original
    hand clutch must remain engaged (transferring power to the chain) for the cent clutch to work.
    -It was smooth at 15kph.
    I kept my hand clutch operable, lever and all, so that I could still pedal start the engine. The pull start rope can break.
    shaddy likes this.
  3. Fabian

    Fabian Well-Known Member

    You don't need to pedal away from a standing start if you get a SickBikeParts shift kit.



    The pull-start rope can break but breakage can be greatly reduced by smothering the rope in Teflon grease. Having a high compression cylinder head can add to rope breakages because the engine sometimes tries to spin backwards off the compression stroke when stopping the engine. This allows engagement of the the pawl system (when in reverse rotation) which tries to pull the rope + handle back through the pull start housing, placing great strain on the rope; causing early failure.
    The other problem that can occur is physical contact between the rope drum and the pawl housing, which applies torque to the rope drum; trying to pull the rope and handle through the housing. This problem can be solved by adding magneto gaskets (spacing the pull start housing away from the pawl mechanism) till the rope drum is no longer making physical contact.

    For the most part though, lubrication of the rope and internal drum gives significant improvement to the life of the pull-start.
    shaddy likes this.
  4. shaddy

    shaddy New Member

    this means that the small gear attached to the cent clutch doesn't rotate with the crank shaft at idle , and when the rpm increase the clutch engaged with the small gear and transmit power to large gear to the other side sprocket and chain ) this explain why we should remove a key fixed the old small gear with crank shaft ,
    another thing , if i increase the outer diameter of rear sprocket to 50 teeth , this can increase torque and help to run without pedal assist ?
  5. shaddy

    shaddy New Member

    what is SickBikeParts shift kit ? and where can i get it , can i get the link please
  6. Fabian

    Fabian Well-Known Member

    Yes, you will have improved low speed torque to enable operation without pedal assist. The other advantage is to improve the ability of the bike to climb hills.

    My suggestion is to get the Deluxe kit as it comes with all of the tools you will need, but most importantly, it comes with the rebuildable, heavy duty freewheel bearing:


    I would also look into the idea of purchasing the optional sprocket sizes; allowing operation of the front derailleur; enabling use of both low range and high range gearing

    Last edited by a moderator: Dec 15, 2015
    shaddy likes this.
  7. shaddy

    shaddy New Member

    fantastic idea , i have 3 front sprocket and 8 rear that gives 24 difrerent speed , this can solve every thing,,
    thanks alooooooooooooooot Fabian ,
    Last edited by a moderator: Dec 15, 2015
  8. Fabian

    Fabian Well-Known Member