Centrifugal Clutch / Manual Clutch options

Discussion in 'Frame Mounted Engines' started by Pezz, Dec 17, 2008.

  1. Pezz

    Pezz New Member

    G'day All

    Im building up a 160cc two stroke single into a Pushbike frame.
    It will be ported and running an expansion chamber.
    I am running a chain based reduction drive and need a clutch.
    I will post a thread as it comes together.

    My main concern is finding/making a suitable clutch.
    I am in a scrapheap challenge with some friends to build and race Motored Pushbikes around a 100acre farm paddock.

    Deal is it had to built for be under $200.

    I have a Honda CT110 postie Bike engine which is seized but will try to remove the clutch to see if I can modify it.

    Just wondering if anyone has any info on a simple clutch design.
    Probably around 8-10HP. I know I can buy one but I want to build something up.


  2. Mountainman

    Mountainman Active Member

    have you thought about slip belt
    tension lever to idle pully

    ride that thing
  3. Pezz

    Pezz New Member

    I had, but what ways are there to ensure there was enough slip to make it work with enough grip:thinking:

    Hence a modified M/cycle clutch was an option.

    Might have to design a simple one and distribute
  4. rbtp

    rbtp New Member

    centrifugal clutch

    I just looked on ebay and there were a few used centrifugal clutches without bids closing today. You might find a deal for little $$. The trick is finding something that engages at the right rpm range and mates to your engine.

    What's your output shaft like?
  5. Pezz

    Pezz New Member

    Well how does this sound :idea:

    I can buy the 50cc pocket bike clutches on ebay for $10.
    CF clutch.JPG
    I was thinking of machining up a piece of pipe to 75mm ID
    Putting in a bearing carrier on both ends.
    The shaft up the centre has a key way and slide in 3 of these clutches.
    On one end of the shaft have a input sprocket mounted for the engine primary chain.
    On one end of the barrel an output sprocket mounted.

    This should be able to handle the modified Victa engine of 165cc and 6 or 7 HP :)
  6. iron_monkey

    iron_monkey Guest

    Wouldn't you be wearing the pads off very quickly? As they are designed for engines that are much less powerful.
  7. Pezz

    Pezz New Member

    I think it should be fine, as I am running 3 units beside each other.
    The heavy duty ones are for racing and they have the engines tuned for max HP.
    I'm going to go and buy them tomorrow to start working it out. I will post pics and developments as I go. The springs allow 2000rpm before full lock up.

    It will be interesting to see. Thanks for your reply.
  8. iron_monkey

    iron_monkey Guest

    Oops sorry i jumped to conclusions. An interesting venture, post piccies if you can.
  9. ZnsaneRyder

    ZnsaneRyder Member

    160cc 2-stroke on a bicycle would be WICKED!

    Keep us posted!!!
  10. NssOne

    NssOne New Member

    How about a go-kart torque converter? Comet has one that can handle like up to 8 hp, but i think you need 7/8 or 1" shaft size. It's just a suggestion. You can find one on ebay for less than $200.
  11. Pezz

    Pezz New Member

    With this build we have to build a motorised bike complete for under $200.

    The more I make the less I spend. I kind of like the idea of creating this CV clutch.

    No one esle is building what I need. Again to run on a 160cc Two stroke lawn mower engine. If i get it right It would open up a LOT of different engines.

  12. Pezz

    Pezz New Member

    I have been looking at a few Centrifugal clutch options. Specs below.
    13mm key'd internal with 75mm out Diameter
    One of my concerns is RPM for full engagement. 5000rpm seems pretty high. Probably not for a 50cc Pit bike, but a 160cc 2 stroke Victa . . . .
    If I run this on a jack shaft, which I was going to use to start the reduction, it may not get to full engagement. . . . I was going to run a 5000 red line. But If I up that to 8000rpm it will be very scary :jester:

    I will have a look and see if I can get it on the end of the crank shaft somehow

    Lightweight Aluminum construction
    Heavyweight 1.5mm springs
    Race Clutch fully engages @ (4700 to 5000 rpm), stock engages @ (4000 to 4300)
    Dramatically increases "Off the line" or "Low end" performance.
    This clutch comes with 3 springs attach!