ENGINE
3-9
TIP
The ignition timing is not adjustable.
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4. Remove:
• Digital tachometer
• Timing light
5. Install:
• Timing mark accessing screw
(along with the O-ring
)
EAS20710
MEASURING THE COMPRESSION
PRESSURE
TIP
Insufficient compression pressure will result in a
loss of performance.
1. Measure:
• Valve clearance
Out of specification
→
Adjust.
Refer to “ADJUSTING THE VALVE CLEAR-
ANCE” on page 3-4.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Disconnect:
• Spark plug cap
4. Remove:
• Spark plug
NOTICE
ECA13330
Before removing the spark plug, blow away
any dirt accumulated in the spark plug well
with compressed air to prevent it from falling
into the cylinder.
5. Install:
• Extension “1”
• Compression gauge “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 compression gauge
stabilizes.
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.
d. If the compression pressure is below the min-
imum specification, pour a teaspoonful of en-
gine oil into the spark plug bore and measure
again.
Refer to the following table.
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7. Remove:
• Extension
• Compression gauge
Extension
90890-04082
Compression gauge
90890-03081
Engine compression tester
YU-33223
New
Standard compression pressure
(at sea level)
550 kPa/600 r/min (5.5
kgf/cm²/600 r/min, 78.2 psi/600
r/min)
Minimum–maximum
480–620 kPa (4.8–6.2 kgf/cm²,
68.3–88.2 psi)
Compression pressure (with oil applied into
the cylinder)
Reading
Diagnosis
Higher than without
oil
Piston ring(s) wear or
damage
→
Repair.
Same as without oil
Piston, valves, cylin-
der head gasket or
piston ring(s) possi-
bly defective
→
Re-
pair.
1
2
Summary of Contents for WR125R 2009
Page 1: ...2009 SERVICE MANUAL WR125R WR125X 22B F8197 E0 ...
Page 6: ......
Page 8: ......
Page 24: ...SPECIAL TOOLS 1 15 ...
Page 51: ...LUBRICATION POINTS AND LUBRICANT TYPES 2 26 ...
Page 54: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 29 EAS20410 LUBRICATION DIAGRAMS A 1 4 5 6 7 2 3 ...
Page 56: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 31 1 3 2 4 ...
Page 57: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 2 32 1 Camshaft 2 Crankshaft 3 Main axle 4 Drive axle ...
Page 58: ...COOLING SYSTEM DIAGRAMS 2 33 EAS20420 COOLING SYSTEM DIAGRAMS 9 1 2 6 7 8 3 5 4 ...
Page 66: ...CABLE ROUTING 2 41 A A B B C C A A B B A B C E D 1 2 3 4 5 6 7 8 9 12 10 11 14 13 ...
Page 68: ...CABLE ROUTING 2 43 B B C C A A A B B C C A A B C C 1 2 3 4 3 4 5 6 7 8 9 10 11 ...
Page 78: ...CABLE ROUTING 2 53 ...
Page 81: ......
Page 109: ...ELECTRICAL SYSTEM 3 28 1 a b ...
Page 110: ...ELECTRICAL SYSTEM 3 29 ...
Page 113: ......
Page 142: ...FRONT BRAKE 4 29 Refer to BLEEDING THE HYDRAULIC BRAKE SYSTEM on page 3 19 ...
Page 184: ...CHAIN DRIVE 4 71 ...
Page 248: ...CRANKCASE 5 61 A Left crankcase B Right crankcase A 1 7 11 12 3 14 2 13 4 5 6 8 9 10 16 15 B ...
Page 258: ...TRANSMISSION 5 71 ...
Page 277: ...THROTTLE BODY 7 8 ...
Page 278: ...AIR INDUCTION SYSTEM 7 9 EAS27040 AIR INDUCTION SYSTEM 2 1 3 ...
Page 282: ...AIR INDUCTION SYSTEM 7 13 ...
Page 285: ......
Page 295: ...ELECTRIC STARTING SYSTEM 8 10 ...
Page 297: ...CHARGING SYSTEM 8 12 2 AC magneto 4 Rectifier regulator 5 Main fuse 6 Battery ...
Page 299: ...CHARGING SYSTEM 8 14 ...
Page 313: ...COOLING SYSTEM 8 28 ...
Page 343: ...FUEL PUMP SYSTEM 8 58 ...
Page 369: ......
Page 370: ......