® Mechanic's knowledge

This is a test for anyone who is skeptical as to how much professional mechanics understand their craft, how technically astute they actually are. This is essentially a Big Four (mostly Honda) exercise, mostly vintage, and almost all practical stuff career mechanics deal with every day.


  1. Cite two differences between energy transfer and magneto ignition systems.
  2. What are the differences between Kettering and Capacitor Discharge ignition systems?
  3. Cite the pros and cons of each, glycol and silicone brake fluids.
  4. Why do high performance cams require more valve tappet clearance than do stock cams?
  5. What happens to the current in a series circuit when loads are added?
  6. What happens when an electronic ignition pulser is connected reversed?
  7. When a piston shows excessive wear at the bottom of the skirt, this is due to what fault?
  8. Why do vintage Honda ignition and charging systems have a bolt that has a divit in its center?
  9. Which is more restrictive, a Honda's intake system or its exhaust system, and why?
  10. Describe the three tests that are made when the complaint is pulsating disc brakes.
  11. Why must in-service cylinders never be honed on a Japanese powersports engine?
  12. How is a DC-powered ignition coil grounded?
  13. What is the relationship between engine condition and carburetor settings?
  14. Some of the vehicle's lights glow dimly when the key is turned on despite the lights not actually being turned on. What is the problem?
  15. With what tools is piston-to-cylinder clearance properly measured?
  16. Describe the pros and cons of each, cast and forged pistons.
  17. Describe performing the volt drop test on an ignition coil.
  18. Why is the relationship between carburetor float level and carburetor overflow a tenuous one?
  19. Whether disc or drum type, what causes brake squeal?
  20. What is a charging system's break-even point and how and with what tools is it measured?
  21. An engine's cylinder leakdown test is good but a compression test is bad. What is the problem?
  22. Cite three causes of poor fuel economy not related to the engine or fuel system.
  23. What is the most common cause of oil consumption in a powersports engine?
  24. Describe the performance advantage of the constant velocity (CV) carburetor.
  25. What are the problems with pressure washing powersports vehicles, and what is the worst kind of pressure washing?
  26. Describe how a Power Commander interacts with the stock fuel injection system ECU.
  27. Describe correct precision insert bearing service.
  28. The engine stalls at a stoplight. What carburetor issue is likely?
  29. What is the best-practice method of gauging and adjusting steering bearings?
  30. Explain the purpose of a carburetor air cutoff system and how it accomplishes this.
  31. Describe test-bypassing a charging system regulator in a 1970s Honda four.
  32. Describe two features in how a final drive chain is best lubricated.
  33. List the steps in the correct clutch adjustment process.
  34. What two features define best practice in tubeless street bike tire repair?
  35. Describe the difference between single-action and double-action disc brake calipers and their comparative merits.
  36. In an overhead cam engine, does valve clearance increase or decrease with heat?
  37. If the result of an electric starter draw test is abnormally high, what two parts are indicated and how is the correct one chosen?
  38. What is a keyhole carburetor, what is its purpose, and name one model of Honda on which it is found.
  39. Where is the fast idle system on a 1983 Honda VF750F carburetor?
  40. Describe how the wear patterns differ on intake and exhaust valve seats.
  41. To what area of a 1970s Japanese inline four's engine does a K&N air filter do the most harm?
  42. Describe test-bypassing a charging system regulator in a 1990s Honda four.
  43. The gear opposite a fixed or slider gear in a typical constant mesh motorcycle transmission is always what kind of gear?
  44. Cite three reasons a CV carb's slide might be indexed.
  45. How much volt drop is acceptable at a switch or connector?
  46. Describe a carburetor circuit's air bleed and its purpose.
  47. Name the three significant differences between detonation and preignition.
  48. What is the defining characteristic of a multiviscosity engine oil?
  49. Very few fuel injection throttle bodies on multicylinder engines have adjustable throttle plates. How then are these throttle bodies synchronized?
  50. Considering that they are locked together, why do they have to be synchronized?
  51. An exhaust gas analyzer's CO reading is low and its HC reading fluctuates wildly. What does this indicate?
  52. What does the ignition stop switch on an AC-powered ignition do?
  53. Why must a 1980s Japanese engine's valve adjusting shim always be measured during valve adjustment?
  54. Cite the main technological difference between street bike shocks of the 1970s and today.
  55. When a piston shows excessive wear in the middle of the skirt, this is due to what fault?
  56. What extremely significant thing happened among the Big Four (Japanese) manufacturers in November of 2012?
  57. An engine's cylinder leakdown test is bad but a compression test is good. What is the problem?
  58. Describe how a plugged carburetor jet can cause decreased fuel economy.
  59. What simple maintenance-level adjustment can slightly increase cylinder compression on a low-compression engine?
  60. What happens to the current in a parallel circuit when loads are added?
  61. Explain the advantage of the Serdi (and its many copies) type head-gasket-surface-referencing valve seat machining system over the valve-guide-referencing seat machining systems.
  62. What is the technical reason 1970s Hondas at some point will have low cylinder compression?
  63. What is the easiest way to slightly adjust low speed fuel richness on most computerized fuel injection systems?
  64. Describe the performance advantage of the flat slide carburetor.
  65. What functional effect does raising the oil level have in a 1970s Honda fork?
  66. What is the tuning advantage of Mikuni carburetor jets being marked using a different system than are Keihin carburetor jets?
  67. What is the drawback of all Kettering-based ignition systems?
  68. What one thing has Honda recently done that seriously threatens vintage Honda restoration and maintenance?
  69. How is cylinder compression tested in an engine having an automatic compression release without defeating the compression release?
  70. How much amperage does a 1970s Japanese four's electric starter normally draw?
  71. What will be the performance fault when a constant velocity (CV) carburetor has a torn diaphragm?
  72. A valve seat is too close to the combustion chamber. Which cutter is used to correct this?
  73. A battery tests good and so does the charging system, yet the battery repeatedly becomes drained. What should be done next?

On this page are even more subjects for conversation, should you want them. However, unlike this list, in which best practices are clearly championed and there is therefore little that is controvertible, in the other, larger list there is a lot of material there for debate.

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