Download Print this page

YAMAHA YZ250F(Y) Owner's Service Manual Page 94

Hide thumbs

Advertisement

2. Measure:
• Compressed spring force "a"
Out of specification → Replace.
Compressed spring
force:
Intake:
99–114 N at 29.13 mm
(9.9–11.4 kg at 29.13
mm, 22.27–25.57 lb at
1.15 in)
Exhaust:
126–144 N at 29.30
mm (12.6–14.4 kg at
29.30 mm, 28.44–
32.41 lb at 1.15 in)
b.
Installed length
3. Measure:
• Spring tilt "a"
Out of specification → Replace.
Spring tilt limit:
Intake:
2.5°/1.7 mm (0.067 in)
Exhaust:
2.5°/1.6 mm (0.063 in)
CHECKING THE VALVE LIFTERS
1. Inspect:
• Valve lifter
Scratches/damage → Replace
both lifters and cylinder head.
VALVES AND VALVE SPRINGS
INSTALLING THE VALVES
1. Apply:
• Molybdenum disulfide oil
Onto the valve stem and valve
stem seal.
2. Install:
• Valve "1"
• Valve spring seat "2"
• Valve stem seal "3"
• Valve spring "4"
• Valve spring retainer "5"
To cylinder head.
• Make sure that each valve is in-
stalled in its original place, also re-
ferring to the painted color as
follows.
Intake (middle) "a": Orange
Intake (right/left) "b": Green
Exhaust "c": Purple
• Install the valve springs with the
larger pitch "d" facing upward.
e.
Smaller pitch
3. Install:
• Valve cotter
While compressing the valve spring
with a valve spring compressor "1" in-
stall the valve cotters.
Valve spring compres-
sor:
YM-4019/90890-04019
4. To secure the valve cotters onto
the valve stem, lightly tap the
valve tip with a piece of wood.
4-24
Hitting the valve tip with excessive
force could damage the valve.
5. Install:
• Adjusting pad "1"
• Valve lifter "2"
• Apply the molybdenum disulfide oil
on the valve stem end.
• Apply the engine oil on the valve lift-
ers.
• Valve lifter must turn smoothly
when rotated with a finger.
• Be careful to reinstall valve lifters
and pads in their original place.

Advertisement

This manual also for:

Yz250f 2009, Yz250fy 2009

Comments to this Manuals

Symbols: 0
Latest comments:
  • Dave May 30, 2016 02:21:
    Really good really good really goodj