How I gave my motor gears.

Discussion in 'Introduce Yourself' started by Garp, Aug 23, 2010.

  1. Garp

    Garp Member

    Hi from Australia!
    I had a yearning for a motorized bike since I was a kid but I couldn't find one that was fun in the mountains where you need low gearing most of the time. Eventually the idea became too strong and I set about making one.
    The first version was cobbled together using stuff I had laying about. It was hopeless, the gearing was too high and the pedals had to be removed but the motor ran through the gears.
    My next attempt was much better.
    It can be pedalled normally with no resistance, if you pull start the motor it will idle until you open the throttle and the motor chimes in. I made it 100/1 reduction so 60 pedals pm=6000rpm at the motor in each gear. You can pedal with it, or freewheel and ride it like a little motorcycle, or a bit of both.
    It can get up any hill and it does 40kph on the flat without pedalling.
    All with only 31cc's of 4 stroke Honda.
    It goes flat out for 2 hours or so on a litre of unleaded. It runs at any angle and it has a cooling fan built in.
    I just stripped it down for the first time in 3 years of riding in the mountains. There was no noticeable wear so it must be right.
    I also have a Shimano 4 spd auto hub to try soon.
    It's a little overbuilt so I may try a 60cc Honda powerhead. I also would like to try electric as I think a set of gears would make a small motor a lot more usable.
    I hope you like it, it's a lot of fun.
    If you search "perrincycle" you can find a little movie of me riding it.

    Attached Files:

    Last edited: Aug 23, 2010

  2. G-Superior

    G-Superior Member

    Now, thats unique! One of a kind! Well done and welcome to the forum!
    Hope the see how it works inside!
  3. gothicguy64

    gothicguy64 Member


    so how many gears ?

  4. Garp

    Garp Member

    Cheers, I'm running a 7 speed shimano at the moment.
  5. Garp

    Garp Member

    Thanks G
  6. james65

    james65 Member


    It looks like a commercial dual shaft reducer gear box? If so pretty neat. How heavy?
  7. Al.Fisherman

    Al.Fisherman Active Member

    Welcome... Where's a will there is a way...
  8. loquin

    loquin Active Member

    Hi Garp. Welcome aboard.

    Very nice job with your bike. I'm sure that many members have questions about your design (I know that I do) - might I suggest that, if you don't mind the questions, you start a thread in the Frame-Mounted Drive Train forum ?
    Last edited: Aug 30, 2010
  9. PatrickW

    PatrickW Staff Member

    I, also, would like to know very much how it 'works' in, how it's put together. And welcome to MBc.
  10. mudbug

    mudbug New Member

    :idea:Interesting--Very Interesting !!! :grin5:

    Welcome to the sandpit.
  11. Garp

    Garp Member

    Thank you all for your nice comments.
    This build was just a prototype, If I had the resources I would build it much lighter. I reckon I could get the weight down to 40 pounds without too much trouble.
    Sometimes less is more.
  12. Garp

    Garp Member

    I'm new to forums, if you want to link it or whatever go for your life.
    If you like this one you'll probably enjoy my next project, "Perrincycle lite".
  13. Thats pretty sweet. Looks like alot of engineering went into it.

    Maybe you could start making them and selling them.
  14. ibdennyak

    ibdennyak Guest

    Hey, I'm liking that. I did something similar using a Honda 25 and a mini tiller transmission a few years back. Worked well, but the bushings on the trans were only good for 1500 or so miles. Interested in what trans you used and how you mounted it up.
  15. Garp

    Garp Member

    The trans is a reduction box I adapted. I mounted it on the swing arm for constant tension. It was originally on a 3/4 horse motor so it's way too big, I want it to be elegant.
    Last edited: Aug 24, 2010