Reading Assignment
- Zen and the Art of Motorcycle Maintenance: Chapters 8 – 9
In-Class Discussion
Zen and the Art of Motorcycle Maintenance
- Theme: Classic vs. Romantic – The narrator explains the divide between Classic and Romantic understanding, using piles of sand as an example. The Classicist would classify and subdivide the grains of sand into smaller piles based upon criteria such as grain shape, size, and color. The Romanticist would only see the pile of sand as a whole. This example relates back to the narrator’s allusion to a knife cutting motorcycle functions into parts. Just as piles of sand can be divided according to various classifications, so too can the functions of a motorcycle.
- During the narrator’s trek to Montana, a variety of problems crop up due to the intense heat.
- “Dieseling,” something that happens to the narrator’s motorcycle, occurs when the engine fires without a spark, usually because the reaction happens on the intake cycle rather than on the combustion cycle. Certain engines can ignite a spark without a spark plug, simply by compressing air and fuel at a high enough pressure.
- Sometimes, “dieseling” occurs because an engine that requires high-octane fuel is running on low octane gasoline. When this happens it is sometimes referred to as engine knock.
- Additionally, the narrator notices that his “left exhaust pipe has picked up a bluer color” which indicates that the chrome of the exhaust pipe is overheating.
- A final point that the narrator communicates is the definition of a machine, which he does by describing what Phaedrus is NOT. Specifically, he tells us that Phaedrus is not a machine, because he is not “pistons and wheels and gears moving all at once, massive and coordinated” (page 84).
Shop Class as Soulcraft
- Theme: Crawford argues that early motorcycles weren’t highly convenient or efficient. He cites advances such as automatic spark timing and systems of automatic lubrication for the engine for making the motorcycle more user-friendly.
- Along with these two advancements, there is a general trend towards making things more electronic (or more abstract) and less accessible to the casual user. For example, Crawford explains the premise behind the “idiot light” which serves as a replacement for a driver checking the oil level (by using the dipstick) on their own and instead encourages them to take it into a shop to be serviced. One of the drawbacks to this “advancement” is that drivers are given no explanation of the problem that has occurred and as a result have an even more limited understanding of how to fix their car or motorcycle.
- As the motorcycle’s rpm increases, its centrifugal spark advance (page 63) allows the spark to fire sooner. “Timing advance” is important because in the retarded position (lower speed) the spark can fire after the specified time and in the advanced position (higher speed) it can fire sooner. Early motorcyclists had to be conscious of the kick-starter firing back after the power stroke, especially if the timing has not been properly delayed.
- Theme: Crawford discusses the distinction between a thing and a device, noting, “A thing requires practice while a device invites consumption” (page 66). Going even further, Crawford argues that servicing a thing is even on a different level from designing it.
Calculations
- We found that the speed of a motorcycle whose flywheel moves at 6,000 rpm (rotations per minute) can travel up to 60 miles per hour.
- We calculated this by setting the number of teeth on the engine and the number of teeth on the clutch to be inversely proportional to the rpm of the flywheel and the clutch basket. We found the answer to be 2375 rpm.
- Next, we set the number of teeth on the gearbox and the number of teeth on the rear wheel to be inversely proportional to the answer from above (in rpm) and the rear wheel sprocket. Our answer to this part was 841 rpm.
- From there, we calculated the speed of the rear wheel in feet per minute by using the formula for speed, given that the diameter of the rear wheel was 2 feet. We found that the wheel traveled at around 5,284 feet per minute.
- Finally, we converted our answer into miles per hour and found that our motorcycle could travel up to 60 mph.
Lab
- Top End: measured the cylinder using calipers and a spring loaded indicator. They found the diameter of the set of rings associated with the piston to be the max spec possible (twelve thousandths of an inch).
- Bottom End: disassembled the engine and cleaned the engine case. They began to look on eBay for missing parts.
- Electrical: measured the centrifugal spark advance using a stroboscope.
- Frames, Forks, and Wheels: sandblasted the lower nacelle, cleaned the hubs, and finished the inventory spreadsheet (which can be found under Data).
- Everyone took the online lab safety quiz.
E.W.