How to Adjust Motorcycle Engine Valve Clearance

Valve clearance adjustment should be made with the engine cool, at room temperature. When the valve clearance is to be measured or adjusted, the piston must be at Top Dead Center (T.D.C) on the compression stroke. Below are the general procedure of adjustment.

Valve Clearance Adjustment

1. Remove:
- Spark plug
- Tappet cover (intake side) [1]
- Tappet cover (exhaust side) [2]

2. Remove:
- Timing mark accessing screw (with
O-ring) [1]
- Camshaft end cover (with O-ring) [2]

3. Measure:
- Valve clearance.
   Out of specification → Adjust.
   Valve clearance (cold), example: Intake valve 0.05 ~ 0.10 mm. Exhaust valve 0.10 ~ 0.15 mm.
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Measurement steps:
- Rotate the crankshaft counterclockwise to align the slit [a] on the rotor with the slit [b] on the crankcase cover when the piston is Top Dead Center (TDC).

-  Measure the valve clearance by using a feeler gauge. Out of specification → Adjust clearance.

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4. Adjust:- Valve clearance
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Adjustment steps:
- Loosen the locknut [1]

- Turn the adjuster [2] in or out with the tappet adjusting tool [3] until specified clearance is obtained.
{Turning in | Valve clearance is decreased}
{Turning out | Valve clearance is increased}

-  Hold the adjuster to prevent it from moving and tighten the locknut.
- Measure the vale clearance.
- If the clearance is incorrect, repeat above steps until specified clearance is obtained.
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5. Install:- O-ring
- Tappet cover
If you have any questions regarding the valve clearance sizes of particular motorcycle, feel free to ask me through the comments box.