length YAMAHA TTR50 2006 User Guide

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ENGVALVES AND VALVE SPRINGS
Valve spring
1. Measure:Valve spring free length a
Out of specification → Replace.
2. Measure: Spring tilt a
Out of specification → Replace.
Free length (valve spring):
Intake: 32.45 mm (1.28 in)
: 30.83 mm (1.21 in)
Exhaust: 32.45 mm (1.28 in)
: 30.83 mm (1.21 in)
Spring tilt limit:Intake: 2.5 °/1.4 mm (0.06 in)
Exhaust: 2.5 °/1.4 mm (0.06 in)
Valve seat
1. Measure:
Valve seat width a
Out of specification → Reface the valve
seat.
Valve seat width: Intake: 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in)
: 1.6 mm (0.0630 in)
Exhaust: 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in)
: 1.6 mm (0.0630 in)
Measurement steps:
 Apply Mechanic ’s blueing dye (Dykem) b
to the valve face.
 Install the valve into the cylinder head.
 Press the valve through the valve guide
and onto the valve seat to make a clear
pattern.
 Measure the valve seat width. Where the
valve seat and valve face made contact,
blueing will have been removed.
 If the valve seat is too wide, too narrow, or
the seat is not centered, the valve seat
must be refaced.

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–+ELEC
5. Measure:
Brush length a
Out of specification → Replace.
Brush length wear limit:
3.5 mm (0.14 in)
6. Measure:
Brush spring force
Fatigue/out of specification → Replace as
a set.
Brush spring force: 3.92 ~ 5.88 N
(400 ~ 600 g, 14.1 ~ 21.2 oz)
ASSEMBLY
1. Install:
Brush holder
2. Install:
Armature coil 1
3. Install:
Ring 1
 Starter motor yoke 2
 Front bracket 3
NOTE:
Apply molybdenum disulfide grease lightly
on to the bearings of the starter motor.
 Align the match mark on the armature
assembly with the match mark on the front
bracket.
ELECTRIC STARTING SYSTEM