Generally signs are indicated on the gears. By bringing these signs face to face valve timing is set. If these signs are not there, in that case, we should indicate the signs on both the gears when the engine is opened. If valve timing is to be set on gears which do not bear any signs, No 1 piston is brought on T.D.C. in compression stroke and both the gears are joined. In this stage if we turn the camshaft on one side, the inlet valve should open and when we turn it on the other side, exhaust valve should open.