Chains Chain jammed

Discussion in 'Transmission / Drivetrain' started by jayjmarlo, Jan 17, 2013.

  1. jayjmarlo

    jayjmarlo New Member

    Going down a hill today upon releasing the clutch my chain jammed into the crank where it goes into the motor by the clutch arm. One of the links had been pushed up jamming the chain in place and locking the back tire in place throwing me to a skidded halt. I was able to remove the cover plate by the clutch arm and fix the problem. My question is how do I prevent this from happening? I made the chain tensioner a little tighter for now, was thinking I'd try greasing the chain as well. It's aligned pretty well. I'm running the 66cc chinese 2 stroke. Was pretty dangerous so I'd like to prevent it from happening again. Thanks

  2. Anton

    Anton Administrator Staff Member

    This happens when your chain is too slack. With a proper tension on the chain this can not possibly happen. Try for about 1cm of slack (deviation) from normal position.
  3. Fabian

    Fabian Well-Known Member

  4. crassius

    crassius Well-Known Member

    also, I've seen a few front sprockets that were a bit fatter in the teeth than usual - grinding the tops of the teeth to be a bit pointier (both side-to-side & front-to-back) never hurts
  5. relaxxx

    relaxxx Member

    I had this problem before no matter how tight my chain was. Went through many tensioners and wheel spokes... when it was tight it would just destroy my tensioner when it jammed. I had to get a 420 chain to fix the problem.
  6. Fabian

    Fabian Well-Known Member

    Sounds like you have an alignment issue. The wider width of the 420 chain is potentially masking the problem.
  7. blue 48

    blue 48 Member

    Yup been there snapped chains,spokes, popped tyres ect. ive been lucky enough not to break the casing on the motor though. the stock chains are junk, i spent $40 on a decent chain.
  8. jefuchs

    jefuchs Member

    I had that happen when my chain has popped off my rear sprocket.

    To me, it looks like the inside of the housing can be modified to prevent this. There's enough space inside for the chain to get jammed. Seems like you could fill the excess space with JB weld, and create a path that's wide enough for the chain, but not wide enough for it to jam.
  9. jayjmarlo

    jayjmarlo New Member

    I went with a spring loaded chain tensioner and a kmc 415 chain. So far no problems.