Oil pressure gauge and take-off point adapter (arrow)

3.17 Dial gauge reading of 1.48 mm

• If measuring shaft runout, the shaft must be supported in vee-blocks and the gauge mounted on a stand perpendicular to the shaft. Rest the tip of the gauge against the centre of the shaft and rotate the shaft slowly whilst watching the gauge reading (see illustration 3.18). Take several measurements along the length of the shaft and record the

• A dial gauge with suitable adapters can be
used to determine piston position BTDC on
two-stroke engines for the purposes of ignition
timing. The gauge, adapter and suitable length
probe are Installed in the place of the spark
plug and the gauge zeroed at TDC. If the
piston position is specified as 1.14 mm BTDC,
rotate the engine back to 2.00 mm BTDC, then
slowly forwards to 1.14 mm BTDC.

Cylinder compression gauges

• A compression gauge is used for measuring cylinder compression. Either the rubber-cone type or the threaded adapter type uan b«usbU. TIio latter is preferred to ensure a perfect seal against the cylinder head. A 0 to 300 psi (0 to 20 Bar) type gauge (for petrol/gasoline engines) will be suitable for motorcycles.

• The spark plug Is removed and the gauge either held hard against the cylinder head (cone type) or the gauge adapter screwed into the cylinder head (threaded type) (see illustration 3.20). Cylinder compression is measured with the engine turning over, but not ninning - carry out the compression test as described In

• Oil pressure is measured with the engine
running (at a specific rpm) and often the
manufacturer will specify pressure limits for a
cold and hot engine.

Straight-edge and surface plate

• If checking the gasket face of a
component for warpage, place a steel rule or
precision straight-edge across the gasket face
and measure any gap between the straight­
edge and component with feeler gauges (see
illustration 3.22). Check diagonally across the
component and between mounting holes (see
illustration 3.23).

Дата добавления: 2015-10-29