1. Check the valve clearance.
- The recommended valve clearance for the Honda Rancher 420 is 0.10-0.15 mm (0.004-0.006 in).
- To check the valve clearance, you will need to remove the valve cover.
- Once the valve cover is removed, you will be able to see the valve clearances.
- If the valve clearance is too small, the valve will not open properly and the engine will not run smoothly.
- If the valve clearance is too large, the valve will not close properly and the engine will lose compression.
2. Adjust the valve clearance.
- If the valve clearance is not within the recommended range, you will need to adjust it.
- To adjust the valve clearance, you will need a feeler gauge and a wrench.
- Insert the feeler gauge between the valve stem and the rocker arm.
- If the feeler gauge fits too loosely, the valve clearance is too large and needs to be decreased.
- If the feeler gauge does not fit at all, the valve clearance is too small and needs to be increased.
- To adjust the valve clearance, turn the adjusting screw on the rocker arm until the feeler gauge fits snugly between the valve stem and the rocker arm.
3. Repeat steps 1 and 2 for the other valves.
4. Reinstall the valve cover.
