Clutch, Timing and Compression

Clutch, Timing and Compression xjcdadmin Thu, 09/20/2018 - 10:47

CLUTCH ADJUSTMENT

1.      Loosen:
•  Adjuster locknut (1)

2.      Adjust:
•  Clutch lever free play (3) 
(by turning adjuster (2) in or out)

Free play:
2-3 mm (0.08
- 0.12 in)

If free play can not be adjusted, adjust by clutch cable length adjuster.

3.      Loosen:
•  Adjuster locknut (1)

4.      Adjust:
•  Clutch lever free play
(by turning clutch cable length adjuster (2)
)

 

IGNITION TIMING CHECK

Flywheel is marked as follows:

(1) TDC for No. 1 cylinder

(2) Firing range for the No. 1 cylinder

1. Check:
• Ignition timing

Ignition timing check steps:
•   Remove the cover.
•   Connect the Timing Light (YM-33277) i to No. 1 cylinder spark plug lead.
•   Warm up the engine and let it idle at the specified idle speed of 1,050 ± 50 r/min.
•  Visually check the stationary pointer in the timing window to verify it is within the required firing range indicated on the flywheel.

Incorrect firing — Check timing plate and/or pickup assembly (tightness damage)

Refer to CHAPTER 6, "ELECTRICAL" for further information.

(1) TDC for No. 1 cylinder

(2) Firing range for the No. 1 cylinder

 

COMPRESSION PRESSURE MEASUREMENT

NOTE:
Insufficient compression pressure will result in performance loss.

1.      Measure:
•  Valve clearance

Out of specification — Adjust.

2.      Warm up the engine.

3.      Remove:
•  Spark plugs

Compression pressure measurement steps:
•   Install the Compression Gauge (YU-33223) (1) using an adapter.
•   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.
•   Check readings with specified levels (See chart).

Compression Pressure (at sea level): 
Standard: 1,078 kPa (11 kg/cm2, 156 psi)
Minimum: 882 kPa (9 kg/cm2, 128 psi)
Maximum: 1,176 kPa (12 kg/cm2, 171 psi)
 

 

When cranking the engine, ground all of the spark plug leads to prevent sparking.

•   Repeat the previous steps for the other cylinders.
•   If pressure falls below the minimum level:
1.    Squirt a few drops of oil into the affected cylinder.
2.   Measure the compression again.

Compression Pressure (with oil introduced into cylinder)

Higher than without oil

Worn or damaged pistons

Same as without oil

Defective ring(s). valves, cylinder head gasket or piston is possible.

Above maximum level

Inspect cylinder head, valve surfaces, or piston crown for carbon deposits.

NOTE:
The difference between the highest and lowest cylinder compression readings must not vary more than the specified value.

Difference Between Each Cylinder: 
Less than 98 kPa (1 kg/cm2,14 psi)