Potential geared engine alternative

Discussion in 'General Questions' started by sorry dog, Sep 28, 2015.

  1. sorry dog

    sorry dog New Member

    I've been getting ready to order a China girl kit for my old Diamond Back mtn bike that I don't ride anymore. Only thing I've been waiting on is that I really want gears of some kind, so I've been studying the different ways that has been achieved by others here and other forums. At first the internal geared hub looks promising, but durability looks really suspect on any installations with decent power (I weigh 210 so that won't help either) so I've dismissed that route. That really only leaves using the chain derailleur. The kit that installs one way bearing on the pedal crank looks real nice but is also pricey. However, I was considering another possibility that might work...

    What if I used a jackshaft to switch the side the motor drives off of and bring the drive sprocket lower so that it could directly drive the 7 gear hub and derailleur. Then I would switch the pedal sprockets to the left side of the frame and have those drive the sprocket that is used in a normal installation. The only catch is some kind of one way bearing would have to be added to that sprocket. It would only have 1 speed for pedaling but that only get back home back-up riding anyway.

    Now, there's one more possibility I've discovered internet searching a few days ago and that is a 50cc motorcycle engine gearbox combo. Here's a link of the supplier's alibaba page.


    They will ship a sample engine for a little more, so I was thinking about that.
    Who knows... might make for a great premium kit. I realize it really is just making the bike more motorcycle but if the setup is cheap enough then this is a way to get real gears and not some jerry rigged gearing.

    I'm looking for some comments on either possibility...

  2. wheelbender6

    wheelbender6 Well-Known Member

    It takes a lot of fab work to mount one of the honda clone horizontal engines like the one at your link in a bicycle frame.
    If you don't have welding experience, you are better off with a China girl engine and shift kit like the ones at sickbikeparts.com.
    The engines in your link are good for replacing a 50cc motoped engine. I have also seen those engines used to hop up a 50cc Laser pedal moped.