How to adjust the valve of motorcycle?

There are many kinds of motorcycle engines, and the methods, tools and valve clearance values of different specific motorcycle engines are different. Therefore, the method and process of adjusting the valve should be combined with the specific situation, but the basic principle of adjusting the valve clearance is still the same.

Adjusting the valve clearance should be done when the engine is cooling. Taking the common single-cylinder motorcycle engine as an example, it is necessary to draw a T point on the magneto rotor first, and align it with the timing mark on the magneto cover or casing, so that the piston of the engine is at the compression top dead center. Because the four-stroke engine has two top dead centers in a working cycle, the valve clearance can only be checked and adjusted by compressing the top dead center. Therefore, at the right time, after marking the T-point on the magneto rotor, check whether the valve rocker arm is in a relaxed state. When the magneto rotor is gently shaken, the valve rocker arm will not move. This is the compression top dead center, and then the valve lash can be checked and adjusted. If the valve rocker arm is too tight and there is no gap after the timing is appropriate, the valve rocker arm will move when the magneto rotor shakes slightly, instead of compressing the top dead center. It is necessary to turn the magneto for another turn, readjust the timing, make the valve rocker arm in a relaxed state, and gently shake the magneto rotor, so that the valve clearance will not move. At this time, the valve clearance can be checked and adjusted.

In order to check and determine the valve clearance, it is best to use a special tool feeler. Different motorcycle engines have different valve clearances, so it is necessary to have motorcycle engine maintenance parameters. When checking the valve clearance, according to the valve clearance parameters of motorcycle engine, insert a suitable feeler between the adjusting screw of valve rocker arm and the valve stem to check the valve clearance. If the valve clearance value is not appropriate, loosen the lock nut of the valve rocker arm adjustment screw, turn the valve rocker arm adjustment screw, adjust the valve clearance to the specified value, and then tighten the lock nut of the valve rocker arm adjustment screw. Finally, check whether the valve clearance is correct. It is best to turn the magneto several times and re-align it to check whether the valve clearance is correct.