Yamaha RAPTOR YFM125RA User Manual

VALVES AND VALVE SPRINGS
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3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
•Valve face
Pitting/wear → Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than
the body of the valve stem → Replace the
valve.
5. Measure:
• Valve margin thickness “a”
Out of specification → Replace the valve.
6. Measure:
• Valve stem runout
Out of specification → Replace the valve.
TIP
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always
replace the oil seal.
EAS24300
CHECKING THE VALVE SEATS
The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
2. Check:
• Valve seat
Pitting/wear → Replace the cylinder
head.
3. Measure:
• Valve seat width “a”
Out of specification → Replace the cylin-
der head.
Valve guide remover (ø5)
90890-04097
Valve guide remover (5.0 mm)
YM-04097
Valve guide installer (ø5)
90890-04098
Valve guide installer (5.0 mm)
YM-04098
Valve guide reamer (ø5)
90890-04099
Valve guide reamer (5.0 mm)
YM-04099
Valve margin thickness
Valve margin thickness (intake)
0.40–0.80 mm (0.0157–0.0315
in)
Valve margin thickness
(exhaust)
0.80–1.20 mm (0.0315–0.0472
in)
Valve stem runout
Valve stem runout
0.010 mm (0.0004 in)
Valve seat width
Valve seat width (intake)
0.90–1.10 mm (0.0354–0.0433
in)
Valve seat width (exhaust)
0.90–1.10 mm (0.0354–0.0433
in)

Yamaha RAPTOR YFM125RA Specifications

General

Brand	Yamaha
Model	RAPTOR YFM125RA
Category	Offroad Vehicle
Language	English