Measuring The Compression Pressure - Yamaha YZF-R15 Service Manual

2. Remove:
Seat
l
Refer to "GENERAL CHASSIS" on page 4-1.
3. Lift the front of the fuel tank. (Do not discon-
nect the fuel hose.)
4. Connect:
Timing light "1"
l
Digital tachometer
l
Timing light
1
5. Check:
Ignition timing
l
s s s s s s s s s s s s s s s s s s s s s s s s
a. Start the engine, warm it up for several min-
utes, and then let it run at the specified en-
gine idling speed.
Engine idling speed
1300–1500 r/min
b. Check that stationary pointer "a" in the magn-
eto cover is within the firing range "b" on the
magneto rotor.
Incorrect firing range → Check the ignition
system.
NOTE:
The ignition timing is not adjustable.
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6. Remove:
Digital tachometer
l
Timing light
l
7. Install:
Fuel tank
l
Refer to "FUEL TANK " on page 7-1.
Seat
l
Refer to "GENERAL CHASSIS" on page 4-1.
8. Install:
Timing mark accessing screw
l
(along with the O-ring
MEASURING THE COMPRESSION
PRESSURE
NOTE:
Insufficient compression pressure will result in a
loss of performance.
1. Measure:
Valve clearance
l
Out of specification → Adjust.
Refer to "ADJUSTING THE VALVE CLEAR-
ANCE" on page 3-3.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Remove:
Right front panel
l
Refer to "GENERAL CHASSIS" on page 4-1.
4. Disconnect:
Spark plug cap
l
5. Remove:
Spark plug
l
CAUTION:
Before removing the spark plug, use com-
pressed air to blow away any dirt accumulat-
ed in the spark plug wells to prevent it from
falling into the cylinder.
6. Remove:
Seat
a
l
Refer to "GENERAL CHASSIS" on page 4-1.
7. Lift the front of the fuel tank. (Do not discon-
nect the fuel hose.)
b b
8. Install:
Compression gauge "1"
l
3-8
New )
Compression gauge
ENGINE