Yamaha TMAX 2020 Service Manual

5-26
VALVES AND VALVE SPRINGS
3. Eliminate:
• Carbon deposit
(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 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 re-
place the valve stem seal.
EAS30285
CHECKING THE VALVE SEATS
The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
• Carbon deposit
(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 cylinder
head.
a. Apply blue layout fluid “b” onto the valve
face.
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
onto the valve seat to make a clear impres-
sion.
d. Measure the valve seat width.
TIP
Where the valve seat and valve face contacted
one another, the blue layout fluid will have been
removed.
4. Lap:
• Valve face
• Valve seat
TIP
After replacing the cylinder head or replacing the
valve and valve guide, the valve seat and valve
face should be lapped.
Valve stem runout
0.010 mm (0.0004 in)
G088965
Valve seat contact width (intake)
0.90–1.10 mm (0.0354–0.0433
in)
Limit
1.6 mm (0.06 in)
Valve seat contact width (ex-
haust)
0.90–1.10 mm (0.0354–0.0433
in)
Limit
1.6 mm (0.06 in)
G088966
G088967

Yamaha TMAX 2020 Specifications

General

Displacement	562cc
Bore x Stroke	70.0 mm x 73.0 mm
Compression Ratio	10.9:1
Fuel System	Fuel Injection
Ignition System	TCI
Transmission	V-Belt Automatic
Rear Suspension	Swingarm
Front Brake	Hydraulic dual disc, Ø267 mm
Rear Brake	Hydraulic single disc, Ø282 mm
Front Tyre	120/70R15M/C 56H
Rear Tyre	160/60R15M/C 67H
Overall Length	2, 200 mm
Overall Width	765 mm
Seat Height	800 mm
Wheelbase	1, 575 mm
Wet Weight	218 kg
Fuel Tank Capacity	15 litres
Engine Type	Liquid-cooled, 4-stroke, DOHC, 4-valve
Maximum Torque	55.7 Nm @ 5, 250 rpm
Front Suspension	Telescopic fork
Overall Height	1, 420mm