1. Run the engine until it is warmed up.
2. Stop the engine and disconnect the 2P connector from the stop solenoid in order to inject fuel.
3. Remove the fuel tank and all injection nozzles.
4. Set a compression tester (Code No. 07909-30208) with the adaptor to the nozzle hole (Nozzle hole thread size : M20 × 1.5).
5. Keep the engine stop lever at “Stop Position”.
6. While cranking the engine with the starter, measure the compression pressure.
7. Repeat steps 4 through 6 for each cylinder.
8. If the measurement is below the allowable limit, apply a small amount of oil to the cylinder wall through the nozzle hole and measure the compression pressure again.
9. If the compression pressure is still less than the allowable limit, check the top clearance, valve and cylinder head.
10. If the compression pressure increases after applying oil, check the cylinder wall and piston rings.
• Check the compression pressure with the specified valve clearance.
• Always use a fully charged battery for performing this test.
• Variances in cylinder compression values should be under 10%.
Valve clearance must be checked and adjusted when engine is cold.
1. Remove the fuel tank, the head cover, the glow plugs and the timing window cover on the clutch housing.
2. Align the “1TC” mark line on the flywheel and center of timing window so that the No. 1 piston comes to the compression or overlap top dead center.
3. Check the following valve clearance marked with “” using a feeler gauge.
4. If the clearance is not within the factory specifications, adjust with the adjusting screw.
Valve clearance Factory specification
0.18 to 0.22 mm
0.0071 to 0.0086 in.
• The “TC” marking line on the flywheel is just for No. 1 cylinder. There is no “TC” marking for the other cylinders.
• No. 1 piston comes to the T.D.C. position when the “TC” marking is aligned with the center mark of timing window on clutch-housing. Turn the flywheel 0.26 rad (15 °) clockwise and counterclockwise to see if the piston is at the compression top dead center or the overlap position.
Now referring to the table below, readjust the valve clearance. (The piston is at the compression top dead center when both the IN. and EX. valves do not move; it is at the overlap position when both the valves move.)
• Finally turn the flywheel 6.28 rad (360 °) and align the “TC” marking line and the center mark of timing window. Adjust all the other valve clearance as required.
• After turning the flywheel counterclockwise twice or three times, recheck the valve clearance, firmly tighten the lock nut of the adjusting screw.