Yamaha XT660X Service Manual

3 - 21
CHK
ADJ
CHECKING THE IGNITION TIMING/
MEASURING THE COMPRESSION PRESSURE
4. Detach:
• timing light
5. Install:
• timing mark accessing screw
EAS00067
MEASURING THE COMPRESSION
PRESSURE
NOTE:
_
Insufficient compression pressure will result in
a loss of performance.
1. Measure:
• valve clearance
Out of specification → Adjust.
Refer to “ADJUSTING THE VALVE
CLEARANCE”.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Disconnect:
• spark plug cap
4. Remove:
• spark plug
CAUTION:
_
Before removing the spark plug, blow away
any dirt accumulated in the spark plug well
with compressed air to prevent it from fall-
ing into the cylinder.
5. Install:
• compression gauge 1
• adaptor (compression gauge) 2
Compression gauge
90890-03081
Adaptor (compression gauge)
90890-04082
1
2

Yamaha XT660X Specifications

General

Displacement	660cc
Bore x Stroke	100.0 mm x 84.0 mm
Compression Ratio	10.0:1
Fuel System	Fuel Injection
Ignition System	TCI
Transmission	5-speed
Final Drive	Chain
Rear Brake	Single disc, Ø 245 mm
Front Tyre	120/70 R17
Rear Tyre	160/60 R17
Maximum Power	48 HP (35.3 kW) @ 6, 000 rpm
Maximum Torque	58.4Nm (43.1lb-ft) @ 5, 250rpm
Front Suspension	Telescopic fork
Rear Suspension	Swingarm, (link suspension)
Fuel Tank Capacity	15 litres
Engine Type	Liquid-cooled, 4-stroke, single cylinder, SOHC, 4-valves