60 Tiger Cub Motorcycle

FRS 106, Michael Littman – Spring 2019

Week 3: Thursday

Last Lab Recap

Detailing: Went down into shop and looked at hubs with the wheel group, then went back to sanding the oil and gas tanks. They also experimented with the grit of the sandpaper (600, 800, + 1000 grit).

Electrical: Learned how to sauter: how to cut the wires, take out the insulation, and solder them together. Also looked at the wiring harness.

Top and Bottom End: Wanted to check the oil pump system, but to do that they had to remove the gears. They also learned why the clutch plates are designed the way they are and that there is a duplex chain on our motorcycle.

Frame: Started by disassembling the fork, then they degreased the parts. Today, they’re going to put them through the part cleaner in the shop.

Wheels: Sanded the hubs


Finding Top Speed of the Motorcycle

Problem: There is a chain connecting the crankshaft to the clutchbasket. There are two sprockets connected to the clutchbasket; in the highest gear these two sprockets spring together. That will turn the rear wheel. We want to figure out how fast the rear wheel is spinning when the crank is 6000rpm (top engine rpm). The second thing we want to figure out is how fast would the motorcycle be going at that pace.

Answer: The motorcycle is going 60mph.

A sprocket engaging with the chain (meshes with the chain); a gear has teeth, which look very similar to the procket, and they mesh with another gear, so there’s a point of contact and when you turn one, you end up turning another (involute shape, roll on one another).

Reading Discussion

  • Discussion Leader: Charles
  • Chapter 11: Wake up and have a nice morning in the hotel, decide to take a different route which goes by Yellowstone Park, talks about Phaedrus and lateral truth, then goes into Phaedrus’s history in the army in Korea.
    • P.124, engine backfires because there wasn’t enough oxygen. Backfiring through the intake can be harmful; the flame will burn all the fuel in the intake all the way up to the carburetor, creating a volume of air with no air and no fuel. This means the engine runs lean and if this keeps happening, the engine can stall out. Higher than normal engine temperatures, the engine being deaccelerated too quickly, too much alcohol in the fuel, etc. can all cause backfire.
    • A priori motorcycle: Narrator explains that Hume’s approach got Kant thinking. Kant introduces the idea of reason. A priori is knowledge that’s theoretical; for example, when driving a motorcycle you know that gas is being used. Even though you can’t see or sense it, you know it’s happening and can reason that gas is being used.
  • Chapter 12: Wake up in the hotel again and start talking about the DeWeeses, who they’re going to stay with the next day. The narrator starts talking about how Phaedrus knew them in college.
    • A lot of electrical problems are mechanical: if something’s not working, shake it.
  • Chapter 13: They’re going to Boseman. The narrator talks about how he tried to discredit the university he worked with and his students disagreed with him. He describes what the mission of the university is: to seek truth.

Week 3: Tuesday

Last Class Lab Recap

Bottom and Top End: They continued to take apart the engine. They took off another cover and started looking in to see what was happening on timing side; some weird pieces were found and they dug into the manuals to figure out how to get a couple pieces out. They also removed the cam. There was a problem with a piece near the transmission; there was a nut and when it turned with a wrench, the whole engine turned. A pin was needed to lock the flywheel so they could turn the nut. Also, the engine was identified as dry sump, meaning that the motorcycle was not circulating oil. Compared rotation of crank to rotation of rear sprocket (last class). Close ratio transmission

Transmission: A set of gears that is between the crankshaft and the wheels. It allows you to improve the mechanical advantage going from the engine to the wheel. For example, bikes have a low and high gear; low gear lets you get up a hill and high gear lets you go fast. The transmission does the same thing for a motorcycle.

Electrical and Wheels: Read power generator section of the manual, then went outside, filled the generator with oil and fuel and got it running. The manual says don’t operate without grounding it, but they did it anyway. The manual says that as a disclaimer, since grounding makes certain that you never get a shock.

Frame: Told to either powdercoat or bondo the hubs. Al said that the indents were less than 1/16th of an inch so they just used putty. Glen was skeptical about this solution.

Detailing: Sanded down the headlight, oil and gas tanks to clean off the paint and take off orange peel. They wet-sanded so that grit wouldn’t fill up the sandpaper. However, a thicker grit would make sure the paint sticks; on a smooth surface, the paint won’t stick as well. The wet sanding will leave a smooth finish, so they’ll need primer to make sure that the paint sticks.

Reading Discussion

  • Discussion Leader: Maya
  • Chapter 8 Summary: They’re in Montana. They get in really exhausted and the innkeeper doesn’t understand them because they’re acting loopy. He spends a lot of time fixing the motorcycle and describes the difference between classical and romantic. They like the town and there’s a part where he goes to buy the jets.
    • P. 96 tappet adjustment: He was tuning the motorcycle because he heard a noise that sounded like a loose tappet. Since they were at a higher altitude, the elevation made the engine richer. He finds that the porcelain inside the plugs is dark which means the engine is running rich; then he went to go check the cylinders to see which one it was.
    • He was afraid that the connecting rod would tear itself free and destroy the engine.
    • Also mentioned that jets needed to be changed in the carburetor. At high altitude, there is less oxygen, and putting in too much fuel causes the engine to run rich. He put in a smaller jet to have the correct balance of air and fuel.
  • Chapter 9 Summary: Primarily focuses on the scientific method, but near the end they narrowly avoid getting into an accident.
    • P. 104, misfiring of the engine is caused by bumps in the road: Bumps can cause misfires in multiple ways; for example, creating bad electrical contact, causing the throttle can open briefly, etc.
    • P. 107 Induction vs. Deduction. He talks about testing the battery to figure out what’s happening in the electrical system.
    • He talks about the scientific method and how to create a hypotheses.
      • “Asks the right questions, choose the right tests, and draw the right conclusions”
  • Chapter 10 Summary: This chapter was about Phaedrus and how he was successful in school because he wanted to understand science. However, he moved on to philosophy to understand the questions science couldn’t answer and ends up being expelled from school.
    • P.113, Discusses how science is always advancing

Electricity Demo

  • Voltage can be produced with a moving magnet. You would find that the signal goes positive to negative and back to positve. When the field is increasing, it is positive and when it is decreasing, it is negative. Diodes on this model lets current go in only one direction.
  • There are three sets of coils. To run the motorcycle ignition system, you only need one set. Another set is needed for the lights and another for the horn.
  • Self-Induction
  • Energy can be stored in an inductor
  • There is simulation software for the Electrical team that can help with planning for the motorcycle

Readings for Thursday: Chapters 11-13

Week 2: Thursday

Last Class Lab Recap

  • Top and Bottom End: continued to dismantle the engine by removing the engine covers
    • John explained how the gear shifts work, and we thus figured out the gear rations through calculating the number of turns on the crankshaft that completed one turn on the rotor for each gear
      • after conversions, our motorcycle is extra close, which means it is designed for racing
        • 1st gear is a low gear made for moving, and 2nd gear onwards allows for high speeds
    • pulled head off and saw the movement of the piston
    • the oil chamber on the clutch side was full of grit making the oil look black, representing a new problem in the cycle
  • Electrical/Wheels- checked for rims that would fit the ’60 cub, discovering that we need the 19in and 18in wheels
    • also checked to see which spokes that we had to see if it matched with the hub
    • hubs have two flanges: since the hubs are not symmetrical, so the spokes come out of different angles
      • had to figure out the handedness of the rim, and whether they were the right rims
  • Detailing- took off headlights, gas, and oil tanks to ultimately take down to shop and paint today
  • Frame- sandblasted the hubs, but sandblasting left the hubs rough, so now need to figure out how to make the hubs smooth
    • options: bondo or send it out for powder coating

Reading Discussion

  • Discussion leader: Marina
  • Chapter 5 Summary: they stopped for breakfast, talked about John’s handbrake issues, go camping and discover that Chris has mental health problems
    • p. 52- checks engine temperature, and it has a normal valve clatter
    • p. 53- John’s handlebars start flipping because it is too loose, so they were going to use a shim (a flat strip of metal)
      • collars were pinched shut, yet it was still not tight enough
      • beer cans work as good shims because they are a generally stable soft material
  • Chapter 6 summary: on the road trip, it is extremely hot, and narrator introduces Phaedrus and the classical vs romantic philosophy debate
    • p. 68- thread stripped in chain adjustment, but can adjust chain by sliding
      • to tighten or loosen chain, loosen the axle nut to use the chain adjuster to adjust the wheel back and forth: this stretches the chain
      • if threading is messed up and there is no adjuster, can whack with a hammer on both sides of the rod
    • p. 73- explanation about the different parts of a motorcycle
      • rectifier- fixes the way the current goes–> converts AC (alternating current) to DC (direct current)
      • flywheel- wheel connected to the connecting rod–> stores rotational energy
      • distributor (aka points system in a single cylinder vehicle)- rotating sets of contacts that distributes the sparks from one cylinder to another
        • relative timing of the spark affects engine performance
          • retarded- late
          • advanced- afterwards
  • Chapter 7 Summary- learn more about Phaedrus: the group enters a town, and the narrator recants his hospitalization and electric shock therapy, and Phaedrus represents the previous life of the narrator (ghost)
    • Idea of differences between Romantics and Classicists
      • Romantics- trying to understand the whole system- artistic view
      • Classicists- focus on science and understanding more about the individual parts

Reading for Next Week: Tuesday: Chapters 8-10, Thursday: 11-13

Week 2: Tuesday

Question about last lab –

Blue Motorcycle: What needed to be detached from the motor to remove it from the frame?

  • Oil lines on the bottom (feed and return) and on the head (two circles)
  • gas line and carburetor (along with the slide)
  • electrical wiring/points system
  • clutch cable
  • valve covers
  • one of the studs (removed with trick turn: tightening of two different nuts, then unscrewed together)
  • engine bolts
  • spark plug wire

Sandblasting- sandblast gun shoots air over a tube which creates a vacuum, and sand thus gets drawn up the tube and then ejected outwards

  • team covered threads where axles go through with tape (on wheel hubs)
  • sandblasting cleans up rust and takes off paint

Model T Engine model

  • When lightbulbs go off, the valve closes
  • after an explosion, fuel and air come together, which generates heat (raising the pressure by a factor of 7), and the powerstroke happens right after the spark, so the piston gets pushed down, causing the crank to turn
    • What is left in the chamber? C6H18 + O2 –> CO2 + H2O
  • orange valves let hot gas out through exhaust pipe, and white valves let cool gas in from the carburetor
  • in a Model T, there are 4 cylinders, so there is always one running, which keeps the car going

Reading Discussion

  • Discussion Leader: Owen
  • Chapter 3- Thunderstorm, introduction of ghosts/Phaedrus
    • Speedometer measures how fast one is going based on speed of wheel rotations
    • Tachometer refers to rotations per meter of the engine- measures the crankshafts
  • Chapter 4- What to bring on a motorcycle roadtrip, transition back to roadtrip during the super cold temperatures
    • Cotter pins: piece of metal to help put something in place
    • cold chisel- metal used to remove things that are stuck
    • feeler guage- thin piece of metal to see how close two things are

Week 1: Thursday Scribe Notes

General Notes-

  • Groups decided, posted on website
  • Discussion leader – Jack

Reading Discussion-

  • Choke cuts off the air supply from the carburetor, so it runs rich drawing raw gasoline as opposed to gas vapor. Good for when it’s cold but can flood gas tank if it’s too warm (solution to flooded gas tank is pull plus out and air-dry tank).
  • Gas tank feeds float chamber and the pressure difference between the chamber and the carburetor draws the gasoline into the carburetor. When the level of gas falls in the float chamber, the float lowers allowing more gasoline to enter.
  • Four stroke engine (the flywheel stores rotational energy form the explosion of force).
  • Engine knocks are from autoignition.
  • The stop cock connects the tank and the float chamber.
  • Missing is when the pops are missed (comes from the carburetor being starved of fuel).
  • When the piston and the valve heat rapidly the piston expands more than the valve causing the engine to seize.
  • Tappets connect the cam and the pushrod.
  • Point type ignition system: every time the points open it creates a spark of high heat, while the spark in the spark plug is high voltage.
  • Running in: when you put in a new piston and need to wear the piston in.
  • John and Sylvia fear of technology vs. narrator’s belief in engagement in things you own/fix
  • What is best?

Week 1: Tuesday Scribe Notes

General Notes-

  • Groups:

Top End – head, intake/exhaust valves, cylinders, carburetor, exhaust

Bottom End – clutch, transmission, oil

Electrical – wiring, points, coils, timing

Wheels – brakes, rims, spokes, hubs

Frame – fork, swing arm, seat mudguards, tanks

Detailing – Painting, Fasteners

  • Probably will be using Fusion 360 program

Reading Discussion-

  • Compression ratio (7:1 9:1) ratio of volume of cylinder and combustion chamber from when the piston is at the bottom to when it is at the top. Relates to engine power.
  • Square engine (like ours with dimensions 63mmx64mm).
  • Engines are 33% efficient with a third of energy lost in the exhaust and a third lost through excess heat.
  • Dry sump sucks oil out so the fly wheel doesn’t rotate in oil.
  • OHV (over head valves)
  • Clutch (ours is a friction clutch that uses a collection of plates).
  • Our bike has no battery – alternator directly creates the spark).