1. Gather the necessary tools:
- 8mm Allen wrench
- 12mm wrench
- 14mm wrench
- Feeler gauges
- Socket wrench with 10mm socket
2. Remove the air filter:
- Turn the fuel valve to "OFF" position.
- Remove the 4 Allen bolts holding the air filter cover.
- Lift the air filter cover and remove the air filter.
3. Locate the valve adjustment covers:
- The front valve adjustment covers are located on both sides of the cylinder, just below the cylinder head.
- The rear valve adjustment cover is located on the right side of the cylinder, behind the rear cylinder head.
4. Remove the valve adjustment covers:
- Use the 12mm wrench to loosen the 2 nuts on each valve adjustment cover.
- Remove the valve adjustment covers and set them aside.
5. Turn the engine to Top Dead Center (TDC) of the compression stroke:
- Insert the 14mm wrench into the bolt on the crankshaft pulley.
- Turn the crankshaft pulley clockwise until the "T" mark on the pulley is aligned with the indicator mark on the engine.
- Turn engine one additional rotation (two complete revolutions) to adjust the right cylinder for valve adjustment.
- The intake and exhaust valves will both be closed at this point.
6. Measure and adjust the valve clearances:
- Insert a feeler gauge of the correct thickness between the cam lobe and the rocker arm.
- For the intake valve, the clearance should be 0.10-0.15 mm (0.004-0.006 inch).
- For the exhaust valve, the clearance should be 0.20-0.25 mm (0.008-0.010 inch).
- If necessary, use the 10mm socket to loosen the locknut and adjust the valve clearance by turning the adjusting screw.
- Tighten the locknut and recheck the valve clearance.
- Repeat for the remaining valves.
7. Replace the valve adjustment covers:
- Replace the valve adjustment covers and tighten the nuts.
8. Replace the air filter and air filter cover.
9. Turn the fuel valve back to "ON" position.
10. Start the engine and check for any abnormal noises or vibrations.
