Yamaha WR125R 2009 Service Manual

VALVES AND VALVE SPRINGS
5-22
2. Measure:
• Compressed valve spring force “a”
Out of specification → Replace the valve
spring.
3. Measure:
• Valve spring tilt “a”
Out of specification → Replace the valve
spring.
EAS24340
INSTALLING THE VALVES
The following procedure applies to all of the
valves and related components.
1. Deburr:
• Valve stem end
(with an oil stone)
2. Lubricate:
• Valve stem “1”
• Valve stem seal “2”
(with the recommended lubricant)
3. Install:
• Lower spring seat “1”
• Valve stem seal “2”
Free length (intake)
41.71 mm (1.64 in)
Limit
39.62 mm (1.56 in)
Free length (exhaust)
41.71 mm (1.64 in)
Limit
39.62 mm (1.56 in)
Installed compression spring
force (intake)
140.00–162.00 N (14.28–16.52
kgf, 31.47–36.42 lbf)
Installed compression spring
force (exhaust)
140.00–162.00 N (14.28–16.52
kgf, 31.47–36.42 lbf)
Installed length (intake)
35.30 mm (1.39 in)
Installed length (exhaust)
35.30 mm (1.39 in)
b. Installed length
Spring tilt (intake)
2.5°/1.8 mm
Spring tilt (exhaust)
2.5°/1.8 mm
Recommended lubricant
Molybdenum disulfide oil
New
New

Yamaha WR125R 2009 Specifications

General

Engine Type	Liquid-cooled, 4-stroke, SOHC, 4-valve
Displacement	124.7cc
Bore x Stroke	52.0 mm x 58.6 mm
Compression Ratio	11.2:1
Fuel System	Fuel Injection
Ignition System	TCI
Starter System	Electric
Final Drive	Chain
Front Brake	Hydraulic single disc
Rear Brake	Hydraulic single disc
Seat Height	930 mm
Lubrication System	Wet sump
Rear Brake Diameter	220 mm
Overall Length	2, 180 mm
Overall Width	835 mm
Wheel Base	1, 430 mm
Transmission	6-speed
Front Suspension	Telescopic fork
Rear Suspension	Swingarm
Front Tire	80/90-21
Fuel Capacity	8.5 liters
Maximum Power	11.0 kW (15.0 PS) @ 9, 000 rpm
Maximum Torque	12.2 Nm (1.2 kg-m) @ 8, 000 rpm
Transmission System	Constant mesh
Frame	Steel
Oil Tank Capacity	1.15 litres