KINROAD 150 SERVICE MANUAL VERSION 1, DEC., 2005
20
VALVE MECHANISM INSPECTION AND SERVICING
The picture shows the common valve train of a four-stroke engine. This is a kind of overhead valve; its
intake port, exhaust port, camshaft are all located in the cylinder head; the valve bottoms up over the
combustion chamber.
GENERAL INTRODUCTION
The four-stroke engine completes its four stroke with one piston stroke.
Intake stroke
Compression stroke
Expansion stroke
Exhaust stroke
VALVE CLEARANCE ADJUSTMENT
Valve clearance is an important technical parameter.
Make sure that the valve can close tightly under any conditions, especially when the engine is overheated;
there must be certain clearance kept when the valve is in the cold condition. This clearance is called valve
clearance. When the engine is running, the valve clearance should be neither too big, nor too small. So the
valve clearance adjustment is an important procedure in the valve maintenance.
Remove the cylinder head cover.
z
Inspection and adjustment must be done in cold
conditions (below 35
°
C
).