58 Tiger Cub Motorcycle

FRS 106, Michael Littman – Spring 2026

Wednesday 03/18/2026 Notes (Posted by Diana Antonyan)

Wednesday 03/18/2026 

What Each Group Did on Monday

Wheel Group:

  • Cleaned forks, removing oil before sandblasting
  • Measured the leather seat dimensions

Electrical Group:

  • Smoothed the kickstarter using emery paper so it is easier to remove
  • Reinstalled the gasket

Clutch + Oil Group:

  • Team 1:
    • Cleaned the clutch plates
    • Installed the clutch plates and springs
    • Plan: begin working on the carburetor
  • Team 2:
    • Worked on the brakes
    • Identified that the brakes were loose and attempted to fix them

Top + Bottom End Group:

  • Cleaned chains
  • Used electrolysis to remove rust
  • Calculated gear ratios

Demonstration: Rectifiers

  • A rectifier has three visible electrodes and a fourth internal (hidden) connection
  • We need DC (direct current) because the battery has a positive (+) and negative (–) terminal
  • In motorcycles, the positive terminal is connected to ground
  • The term ground comes from using the Earth as a conductor

Purpose of a Rectifier:

  • Converts AC (alternating current) from the alternator into DC to charge the battery

Observations:

  • The rectifier has four terminals:
    • Two labeled AC
    • One labeled +
    • One labeled
  • It operates using diodes

Circuit Simulator Explanation

  • A simulation was shown using a 40 Hz AC source
  • Color indicators:
    • Green = positive
    • Red = negative
  • Yellow dots show the direction of current flow

Key Concepts:

  • Current flows in one direction only in this setup
  • A diode acts like a one-way valve for current

How AC is Converted to DC (Bridge Rectifier)

  • Four diodes are arranged to form a bridge rectifier
  • A resistor is placed in the circuit
  • The AC source is connected to the bridge

How it works:

  • Current takes a zigzag path through different diodes depending on the AC cycle
  • Even when AC reverses direction, the output remains:
    • One side always positive
    • One side always negative

Application:

  • The alternator acts as the AC source
  • The battery receives the rectified DC output

Rectifier Testing Demonstration

  • Red probe connected to AC terminal, black probe to negative terminal → reading of about 0.5 volts
  • When leads are reversed → overload reading, meaning no current flows
  • This demonstrates the one-way behavior of diodes

Discussion: Shop Class as Soulcraft by Matthew B. Crawford

Main Ideas:

  • Emphasizes the value of manual labor and its intellectual demands
  • Argues that repair skills are important and meaningful
  • Suggests manual trades are a valid alternative career path to traditional academic routes

Craftsman vs. Tradesman:

  • Craftsman: more personal, focused on mastery
  • Tradesman: more economically practical and sustainable

Critique of Modern Work:

  • In many office jobs, there is no clear objective measure of success
  • In manual work, success is clearer:
    • If something works, the job was done well

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