Hand tools, measuring instruments and workshop equipment
This domain tests correct selection, use and care of hand tools and precision instruments in a motorcycle workshop. Marks are lost for wrong tool size, measuring without checking zero, and damaging torque wrenches.
Rules
- Use six-point sockets on rusted or high-torque fasteners; twelve-point sockets round hex heads.
- Match spanner size to the fastener. An adjustable wrench is a last resort because it slips and damages flats.
- Torque wrenches are setting tools, not breaker bars. Set the scale, pull smoothly to the click, and release the spring after use. Recalibrate after drops.
- Vernier calipers: close the jaws, check zero, and read square-on to avoid parallax. Micrometers: use the friction thimble, clean the anvils, and read barrel plus thimble.
- Feeler gauges measure clearance by drag, not force; a blade that fits with heavy drag is too thick.
- Dial indicators and magnetic bases measure shaft runout and disc warp. Bore gauges measure cylinder wear at top, middle and bottom, in two planes.
Worked example
Valve clearance specification is 0.08–0.12 mm. A 0.10 mm blade slides with light drag and a 0.15 mm blade will not enter. The 0.12 mm blade is tight, so the clearance is about 0.11 mm and is acceptable. Record the measurement cold or hot as specified.
Traps
Zero error on a vernier; reading a micrometer thimble backwards; using a torque wrench to loosen; measuring a hot engine against cold specifications; forcing a feeler gauge.