56 Terrier Motorcycle

FRS 106, Michael Littman – Spring 2014

Class 8

Reading Assignment

  • Zen and the Art of Motorcycle Maintenance: Chapters 12-13

In-Class Discussion

Shop Class as Soulcraft

Themes:

  • Stochastic arts – include mechanical repair and medicine – work is always variable in constitution because it has not been created by the mechanics/doctors and is not absolutely understood.
  • Attentiveness – Crawford emphasizes the importance of this trait rather than assertiveness in the stochastic arts.

Mechanics

  • Bearings: Packing an open wheel bearing with grease between the inner and outer races – provides lubrication, prevents seizing. Our motorcycle has caged bearings.
  • Swing axle suspension: Allows motorcycle to maintain holding upon hitting a bump – one wheel can go up while the other stays down.
  • Shock absorbers in the back – gas vs. fluid shocks (the former uses air, the latter hydraulic fluid). Gas shocks work better upon hard impact.
  • Improving performance:
  1. Double-barrel carburetor – facilitates air intake at high speeds when air flow is rapid, allowing engine to run better at higher RPMs.
  2. Free-flowing exhaust – better air flow.
  3. Lightened flywheel – engine with heavier flywheel will start up more slowly.
  4. Nitride coating inside bearing – minimizes friction and prevents wear.
  5. Blueprinting, match porting – makes sure everything is within specs and holes align; minimizes turbulence and improves air flow.
  6. Spring strength – ultimately determines speed of engine in terms of valves opening/closing.
  • Signs of wear
  1. Galling – two metal surfaces fuse together from heat, inadequate lubrication; pieces gouged out.
  2. Mushrooming at valve tips – occurs at sites of impact.

Lab:

——

S.Y.