when you adjust valve clearance of your bike's engine, be sure to set 1st the engine to TDC or top dead center. A T-Mark in the magneto should be aligned in the timing mark into the engine's crankcase. But how will you determine if it is already in the TDC? The answer is when there is already a slack on the rocker arm when stamped either intake or exhaust or both intake and exhaust. if there is no slack in the rocker arms turn the flywheel 360 degrees and re-align the T-Mark in the timing mark. Now when you already set the engine into TDC, then it is time to adjust the valve clearance.

In order for the valves to be adjusted properly, a feeler gauge is inserted to measure its clerance otherwise if you adjusted the clearance without using this tool, then chances are that you can damage the engine like those fool mechanics does (no offense). the clearance of the valves is always specified on the manufactuter's manual (see your manual/service manual for more details), and in order to achieve a proper clearance as you adjust the valves, there should be a slight resistance that can be felt as you pull the feeler gauge in the valve tappet. Too much clearance can cause engine noise (tappet noise) and to little clearance could cause drop in compression resulting in bad idling and eventually burned valves because the valves is pushed during the heated period.