Yamaha MM700A Manual page 27

Dial indicators are available in various ranges and grad-
nations and with three basic types of mounting bases:
magnetic, clamp, or screw-in stud. When purchasing a
dial indicator, select the magnetic stand type (Figure 40)
with a continuous dial.
Cylinder Bore Gauge
A cylinder bore gauge is similar to a dial indicator. The
gauge set shown in Figure 41 consists of a dial indicator,
handle, and different length adapters (anvils) to fit the
gauge to various bore sizes. The bore gauge is used to
measure bore size, taper and out-of-round. When using a
bore gauge, follow the manufacturer's instructions.
Compression Gauge
A compression gauge (Figure 42) measures combus-
tion chamber (cylinder) pressure, usually in psi or kg/cm2.
The gauge adapter is either inserted or screwed into the
spark plug hole to obtain the reading. Disable the engine
so it does not start and hold the throttle in the wide-open
position when performing a compression test. An engine
that does not have adequate compression cannot be prop-
erly tuned. See Chapter Three.
Multimeter
A multimeter (Figure 43) is an essential tool for electri-
eal system diagnosis. The voltage function indicates the
voltage applied or available to various electrical compo-
nents. The ohmmeter function tests circuits for continuity,
or lack of continuity, and measures the resistance of a cir-
cuit.
Some manufacturers' specifications for electrical com-
ponents are based on results using a specific test meter.