How does a clutch work?

Discussion in 'Motorized Bicycle General Discussion' started by primusbike, Mar 18, 2011.

  1. primusbike

    primusbike New Member

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    Okay, made it a broad sounding question, but this is rather specific.

    I have found manual clutches for small displacement engines. There are even exploded transmission parts diagrams I have found, but still no answers. My question is, what is pushed or pulled in these to release spring tension and release the clutch packs?

    These are designed to work on lifan engines, 50, 90 and 110cc engines.

    I understand that in a clutch for a car the spring pressure is released by pressing in the throwout bearing. I do not understand what is going on with the lifan clutch.
     

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    #1 primusbike, Mar 18, 2011
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  2. Nougat

    Nougat New Member

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    In general terms: The spinning of the clutch causes the clutch weights to overcome the spring pressure at high RPMs, which cause the clutches to come together. When the engine is turning at a lower RPM, there's not enough spin for the weights to overcome those springs' tension, and the clutches are apart.
     
  3. primusbike

    primusbike New Member

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    No, not a centrifugal clutch. I understand the weights on a centrifugal. Look at the picture of the clutch I am talking about. Its a manual clutch with several stacked fiction plates. One set rides on the shaft the other the housing around the outside of the clutch. The only thing I dont understand is how the spring pressure is released
     
    #3 primusbike, Mar 18, 2011
    Last edited: Mar 18, 2011
  4. Nougat

    Nougat New Member

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    Oh I see. When you pull the clutch lever, the plates separate so the gears can shift without engine load. Let the clutch out, and the plates spring back together, and deliver engine power to the drive train.

    I'm not real good with clutches, but that's about it.
     
  5. primusbike

    primusbike New Member

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    (Just in case anyone is looking at how fast I'm posting, my phone vibrates every time I get an email.)

    Thanks Nougat, but Ive established that pulling the clutch lever releases the clutch. My concern is the linkage in between. I am not planning on replacing the clutch in a lifan engine. I want to use a clutch sold to replace the one in the lifan engine. Use it in a completely custom application. Ideally I would mount the clutch to a large cog belt pulley. Custom shaft, custom bearing to support the shaft. My conceptual blank spot is the linkage pushing or pulling some part of the clutch. Does the shaft move? Is there a shaft in the shaft that moves?

    btw thanks nougat for helping me define my question. Hope I'm making sense to people here
     
  6. streetstrip80

    streetstrip80 New Member

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    There are some good diagrams of how the chinese kit engine clutches work on this site. Motorcycle clutches generally work in a similar way. There is a lever on one side of the engine which has a cam on it. This pushes a rod that goes through the center of the shaft. It would be hard to adapt to a cog on an engine with a solid shaft, but it may be possible to rig something up on a custom made hollow jackshaft.
     
  7. primusbike

    primusbike New Member

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    Okay, did a little mspainting to illustrate.

    My questions are in the picture.
     

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  8. Skarrd

    Skarrd Member

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    think of it similar to a car clutch.

    you have the clutch disc (the stacked friction discs)
    and the pressure plate (in this case it's the thing with the springs in it)

    the smaller ones are the dampening springs, they reduce chatter when using the clutch.
     
  9. HseLoMein

    HseLoMein New Member

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    Believe it or not but there are motorcycle clutches in your automatic reansmissions, if you have a 6 speed auto then there are 2 motorcycle clutches in them
     
  10. chrisp

    chrisp New Member

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    So, on the clutch pictured above, there is a cable that goes to it from a hand lever?
    Please excuse what I think is probably a very elementary question.
    If I don't have it in front of me, I have a hard time understanding it.
     

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