Yamaha XT660R S Service Manual

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ENG
VALVES AND VALVE SPRINGS
EAS00237
REMOVING THE VALVES
The following procedure applies to all of the
valves and related components.
NOTE:
_
Before removing the internal parts of the cylin-
der head (e.g., valves, valve springs, valve
seats), make sure the valves properly seal.
1. Check:
• valve sealing
Leakage at the valve seat
→
Check the
valve face, valve seat, and valve seat width.
Refer to “CHECKING THE VALVE SEATS”.
▼▼▼▼ ▼ ▼▼▼▼ ▼ ▼▼▼▼ ▼ ▼▼▼▼ ▼ ▼▼▼▼ ▼ ▼▼▼▼ ▼▼▼
a. Pour a clean solvent
a
into the intake and
exhaust ports.
b. Check that the valves properly seal.
NOTE:
_
There should be no leakage at the valve seat
1
.
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2. Remove:
• valve cotters
NOTE:
_
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
1
and the valve spring compressor attach-
ment
2
.
Valve spring compressor
90890-04019
Valve spring compressor attach-
ment
90890-01243

Yamaha XT660R S Specifications

General

Displacement	660 cc
Bore x Stroke	100.0 mm x 84.0 mm
Compression Ratio	10.0:1
Fuel System	Fuel Injection
Ignition System	TCI
Starter System	Electric
Transmission System	5-speed
Final Drive	Chain
Front Suspension System	Telescopic forks
Front Tyre	90/90-21 M/C 54S
Rear Tyre	130/80-17 M/C 65S
Overall Width	865 mm
Overall Height	1, 230 mm
Seat Height	865 mm
Wheelbase	1, 505 mm
Wet Weight	181 kg
Fuel Tank Capacity	15 litres
Oil Tank Capacity	2.9 litres
Engine Type	Liquid-cooled, 4-stroke, single cylinder, SOHC
Maximum Power	48hp (35kW) @ 6, 000rpm
Frame	Steel diamond
Rear Suspension System	Swingarm, (link suspension)
Front Brake	Single 298mm disc, 2-piston caliper
Rear Brake	Single Disc, 245 mm