60 Tiger Cub Motorcycle

FRS 106, Michael Littman – Spring 2019

Week 10: Thursday Scribe Notes

Recap of Last Week’s Lab

  • Detailing: Primed the oil and gas tank, they are painting today.
  • Frame: Got the seat done!
  • Wheels: Finished one of the wheels with Bill Becker.
  • Top-End: Finished assembling the carburetor, fixed the exhaust pipe, and put the blue bike back together.
  • Bottom End: Didn’t put in the sprocket, therefore had to unseal the case again and put it in.
  • Electrical: Drilled hole in the case cover then re-attached it back on to the bike and tested it.


  • What happens to the rear wheel when you just accelerate? What happens to the tension in the chain? The tension goes up on the top.
  • Spring arm allows the whole wheel to bounce up and down.
  • Braking locks the hub and causes the whole assembly to twist.
    • If not designed well, it will snap. In a previous year, it snapped (due to large stress). Glen drew the part and 3D printed it. Then, manufactured it out of high steel aluminum.
  • Another year found that the last gear on the lay shift is missing a tooth. Believe it case hardened.
  • Involute curve:
    • It has the property, when the gears are matching, one tooth rolls on the other. By having the right shape, you have a low mechanical loss. Sliding causes friction loss.
  • Friction
    • Clutch plates
    • Coefficient of friction
      • F = (Mu) * N
        • F = force of static friction.
        • Mu = coefficient of static friction.
        • N = normal force.
    • To calculate theta, the coefficient of friction.
      • Mu = tan(theta)
  • Friction is important in the motorcycle, without friction motorcycle would not go.

Author: Ben Johnston

Ben Johnston is Senior Educational Technologist in the McGraw Center for Teaching and Learning, a unit of the Office of the Dean of the College, Princeton University.