Checking Ignition Timing; Compression Pressure Measurement - Yamaha XZ550RJ 1982 Service Manual

6. Tighten the adjuster lockout.
Tightening torque:
8 Nm (0.8 m-kg, 5.8ft-lb)
7. Adjust the clutch lever free play.

Checking ignition timing

Check the ignition timing with a timing light by ob-
serving the stationary pointer and the marks
stamped on the flywheel.
1. Remove the emblem plate and timing plug
from the left side crankcase cover.
2. Connect the timing light to the front (#1) cyl-
inder spark plug wire.
3. Start the engine, and keep the engine run-
ning at the specified speed. Use a tachome-
ter to check the engine speed.
Engine Speed: 1,300 ± 50 r/min
4. The stationary pointer (in the timing window)
should be within the firing range shown on
the flywheel. If the pointer is not within the
range or if it is not steady, check the flywheel
and/or pickup assembly for tightness and/or
damage. (See Chapter 7, "ELECTRICAL" for
further information.)
5. Reinstall the generator cover.

Compression pressure measurement

Insufficient compression pressure will result in per-
formance loss and may indicate leaking valves or
worn or damaged piston rings.
1. Make sure the valve clearance is correct.
2. Warm up the engine for 2 ~ 3 minutes; stop
the engine.
3. Remove both spark plugs.
4. Install a compression gauge.
5. Turn over the engine with the electric starter
(make sure the battery is fully charged) with
the throttle wide open until the pressure indi-
cated on the gauge does not increase fur-
ther. The compression should be within the
specified levels.
Compression pressure (at seal level):
Standard: 980 kPa (10 kg/cm
Minimum: 882 kPa (9 kg/cm
Maximum: 1,079 kPa (11 kg/cm
WARNING:
When cranking the engine, ground the spark
plug wires to prevent sparking.
2
, 142 psi)
2
, 128 psi)
2
,156 psi)
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