Chassis; Compression Pressure Measurement; Down Tube Strainer - Yamaha XT550J Service Manual

5. Reinstall the blind plug.
N. Compression Pressure Measurement
Insufficient compression pressure will result
in performance 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 the spark plug.
4. Install a compression gauge.
5. Turn over the engine with the kick
starter with the throttle wide open until
the pressure indicated on the gauge
does not increase further. The compres-
sion should be within the specified
levels.
Compression pressure (at seal level) :
Standard .....
1,079 kPa (11 kg/ cm 2, 156 psi)
Minimum .....
883 kPa ( 9 kg/cm2,
1~8
psi)
Maximum .....
1,177kPa(12kg/cm2, 171 psi)
WARNING:
When cranking the engine, ground the
spark plug wires to prevent sparking.
2-8
,
1. Compression gauge set (special tool P / N. YU-33358)
2. Compression gauge adapter (special tool P / N. YU-33358-3)
6. If the pressure is too low, squirt a few
drops of oil into the cylinder. Measure
compression again. If there is a higher
reading than before (without oil), the
piston rings may be worn or damaged. If
the pressure remains the same after
measuring with the oil, one or both rings
and valves may be the source of the pro-
blem.
CHASSIS
A. Down Tube Strainer
1. Remove the front bracket.
2. Remove the strainer.