3 - 18
INSP
ADJ
IGNITION TIMING CHECK/
COMPRESSION PRESSURE MEASUREMENT
5.Install:
●
Timing plug
6.Detach:
●
Timing light
●
Inductive tachometer
COMPRESSION PRESSURE
MEASUREMENT
NOTE:
●
Insufficient compression pressure will
result in performance loss.
●
Before measuring the compression pres-
sure, the valve clearance should be
adjusted.
Refer to “VALVE CLEARANCE ADJUST-
MENT” section.
1.Place the machine on a level place.
2.Remove:
●
Spark plug
3.Measure:
●
Compression pressure
**********************************
Measurement steps:
●
Install the Compression Gauge
1
.
●
Crank over the engine with the electric
starter (be sure the battery is fully
charged) with the throttle wide-open until
the compression reading on the gauge
stabilizes.
WARNING
When cranking the engine, ground the
spark plug lead to prevent sparking.
●
Check readings with specified levels (see
chart).
Compression gauge:
P/N. YU-33223, 90890-03081
Adapter:
P/N. YU-33223-3, 90890-04082
Compression pressure (at sea level):
Standard: 900 kPa (9.0 kg/cm
2
, 128 psi)
Minimum: 800 kPa (8.0 kg/cm
2
, 114psi)
Maximum: 1,000 kPa (10 kg/cm
2
, 142 psi)
3
Summary of Contents for YFM250XL(C)
Page 1: ...SERVICEMANUAL LIT 11616 12 01 4XE F8197 10 YFM250XL C ...
Page 24: ...GEN INFO 1 10 1 ...
Page 54: ...2 30 SPEC 2 ...
Page 98: ...INSP ADJ 3 44 3 ...
Page 176: ...ENG 4 78 4 ...
Page 186: ...CARB 5 10 5 ...
Page 228: ...6 42 DRIV 6 ...
Page 273: ...8 3 ELEC SWITCH INSPECTION 8 ...
Page 312: ...PRINTED IN U S A YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...
Page 313: ...SUPPLEMENTARY SERVICEMANUAL LIT 11616 14 17 4XE F8197 11 YFM250XN ...
Page 372: ...PRINTED IN U S A YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...
Page 374: ...YFM250XP SUPPLEMENTARY SERVICEMANUAL LIT 11616 15 03 4XE F8197 12 ...
Page 397: ...YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN U S A ...