js mounted clutch...

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by scratchbuilder, Jan 17, 2015.

  1. scratchbuilder

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    Anybody have experience with jackshaft mounted clutch...im thinking its a good thing for the little hs.
     
  2. Chainreaction

    Chainreaction New Member

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    If your motor unit has no gear reduction and you plan on using a jackshaft to go the bicycle crank you'll need some serious gear reduction. If that is the case you'll need to reduce from the motor to jackshaft from maybe 11T to 60T. I assume you mean centrifugal clutch, it would need to be one that locked up at low rpms.
     
  3. scratchbuilder

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    Hey Cr...thx for real...what I'm attempting is..engine 11 t . Js 11.. Over to Centric. C 11 to 60 (35chain) sbp freewheel w/22 back to 7 speed cassette/36 sooo.. Think I'll be able to roll from stop..
     
  4. Chainreaction

    Chainreaction New Member

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    I did a lot of head scratching before I came up with a simpler to figure out gearing best for me. First I wanted the crank RPM (cadence) to be around 90-100 (which is comfortable to pedal) when I am cruizing around 25-30MPH, even if I put a freewheel on it. So basically I need to put a 11T to 36T cassette on it and leave the crank gears.

    I am going to use some 2 cycle motor (49cc maybe) with a centrifugal clutch, that has no gear reduction. So then I have to get the motor that is cruizing at 4,000rpm or so reduced to the crank speed of 90-100RPM. With a jackshaft I need two reductions, one about 14T to 78T and from jackshaft to crank 10T to 84T.

    Sounds like a lot of reduction but I want low geared enough to bum around offroad and something I can peddle assist cruizing around town without the engine screaming or lugging.
     
  5. scratchbuilder

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    wow.. I had no idea. ..thats the kinda ridin I like . Sounds like I might have to get one of those $$$ 42 teeth casstte sprocs..
     
  6. scratchbuilder

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    brnotWell..scratch the js clutch. To much shudder during take off. Maybe not enough reduction?. Sooo..belt primary with tension clutch (2" to 5" ) with 10t to 60 to crank freewheel (sbp shift ) with 24 back to cassette 7 (32) top gear. Take offs require a little slipping,but once rolling...great. Shifting gears is soooo cool. Have only used three so far.. And that was fast enough...with cruising rpm's. The bike is a Kent,with tripple tree forks,disc front.Im anxious to post pics. I understand why everyone has 2or3 builds. I've got the madwagon..but it's fun to ride. I'm thinking fd drive on the Danish cargo bike I built with the long box in front. Thx for the inspiration guys. Once again pics are coming.
     
    #6 scratchbuilder, Jan 31, 2015
    Last edited: Feb 1, 2015

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