Attention: Valve clearances are checked and adjusted only on a cold engine.
Setting the valve clearances correctly is very important because they largely determine the performance of the engine. If the valve clearances are too large, the engine will be noisy and the engine efficiency will be reduced because the valves open too late and close too early. A more serious problem occurs if the valve clearances are too small because the valves cannot close completely when the engine is hot, which can lead to serious engine damage.
Set the piston of the first cylinder to TDC in the compression stroke.
Remove the cylinder head cover.
Counting from the thermostat on the cylinder head, the valves are located as follows.
| Valve number | Cylinder number |
| 1 - Graduation | 1 |
| 2 - Inlet | 1 |
| 3 - Graduation | 2 |
| 4 - Inlet | 2 |
| 5 - Inlet | 3 |
| 6 - Graduation | 3 |
| 7 - Inlet | 4 |
| 8 - Graduation | 4 |
Adjust the valve clearances in the sequence given in the following table. Rotate the crankshaft pulley 180° after adjusting each pair of valve clearances.
| Swinging valves | Adjustable valves |
| 7 and 8 | 1 (outlet), 2 (inlet) |
| 5 and 6 | 3 (outlet), 4 (inlet) |
| 1 and 2 | 8 (outlet), 7 (inlet) |
| 3 and 4 | 6 (outlet), 5 (inlet) |
Use a feeler gauge blade of appropriate thickness to check each gap between the end of the valve stem and the rocker arm. The feeler gauge should fit snugly between the valve and the rocker arm. To adjust, turn the adjuster bolt with a spanner until the desired gap is obtained. The adjuster bolts are of the rigid thread type and do not require a lock nut (see Fig. 2A.7).
Finally, install the cylinder head cover.
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