Yamaha R6 2009 - Measuring the Compression Pressure

ENGINE
3-10
8. Install:
• Air induction system solenoid
Refer to “AIR INDUCTION SYSTEM” on
page 7-15.
• Air filter case
Refer to “AIR FILTER CASE” on page 7-
4.
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
• Rider seat
Refer to “GENERAL CHASSIS” on page
4-1.
EAS20710
MEASURING THE COMPRESSION PRES-
SURE
The following procedure applies to all of the
cylinders.
TIP
Insufficient compression pressure will result in
a loss of performance.
1. Measure:
• Valve clearance
Out of specification → Adjust.
Refer to “ADJUSTING THE VALVE
CLEARANCE” on page 3-4.
2. Start the engine, warm it up for several
minutes, and then turn it off.
3. Remove:
• Side cowling assembly
Refer to “GENERAL CHASSIS” on page
4-1.
•Radiator
Refer to “RADIATOR” on page 6-1.
4. Remove:
• Ignition coils
• Spark plugs
ECA13340
Before removing the spark plugs, use com-
pressed air to blow away any dirt accumu-
lated in the spark plug wells to prevent it
from falling into the cylinders.
5. Install:
• Compression gauge “1”
• Extension “2”
6. Measure:
• Compression pressure
Out of specification → Refer to steps (c)
and (d).
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a. Set the main switch to “ON”.
b. With the throttle wide open, crank the
engine until the reading on the compres-
sion gauge stabilizes.
WARNING
EWA12940
To prevent sparking, ground all spark plug
leads before cranking the engine.
TIP
The difference in compression pressure
between cylinders should not exceed 100 kPa
(1 kg/cm², 14 psi).
c. If the compression pressure is above the
maximum specification, check the cylinder
head, valve surfaces and piston crown for
carbon deposits.
Carbon deposits → Eliminate.
Compression gauge
90890-03081
Engine compression tester
YU-33223
Extension
90890-04136
Standard compression pres-
sure (at sea level)
1600 kPa/400 r/min (227.6 psi/
400 r/min) (16.0 kgf/cm²/400 r/
min)
Minimum–maximum
1350–1650 kPa (195.8–239.3
psi) (13.5–16.5 kgf/cm²)
1
2