Yamaha XT660R S Service Manual

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ENG
2. Measure:
• camshaft lobe dimensions a and b
Out of specification → Replace the cam-
shaft.
3. Measure:
• camshaft runout
Out of specification → Replace.
Camshaft lobe dimensions
Intake
a 43.488 ~ 43.588 mm
(1.7121 ~ 1.7161 in)
<Limit>:
43.388 mm (1.7062 in)
b 36.959 ~ 37.059 mm
(1.4551 ~ 1.4590 in)
<Limit>:
36.840 mm (1.4504 in)
Exhaust
a 43.129 ~ 43.229 mm
(1.6980 ~ 1.7019 in)
<Limit>:
42.983 mm (1.6922 in)
b 37.007 ~ 37.107 mm
(1.4570 ~ 1.4609 in)
<Limit>:
36.886 mm (1.4522 in)
Camshaft runout limit
0.040 mm (0.0016 in)
CHECKING THE DECOMPRESSION
SYSTEM
1. Check:
• decompression system
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a. Check the decompression system with the
camshaft sprocket installed on and the
decompressor pin installed in the camshaft.
b. Check that the decompressor lever pin 1
projects from the camshaft.
c. Check that the decompressor cam 2
moves smoothly.
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2
1
ROCKER ARMS AND CAMSHAFT

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