REbornHONDAneer - With the valve cover off, adjust the valves, sounds like you've been looking for the right things already.

SlprTeg- The crank has more inertia than the valve train, I'm trying to tell you that a cylinder won't entirely fill up with water, but it can fill enough to cause compression high enough that during the compression stroke on one cylinder, it can cause enough of a strain on the cams to slow or halt the motion of the cams while the inertia of the crank and attached pistons is harder to overcome, which can allow enough extra rotation to allow the pistons to contact the valves. Valves hitting pistons do not bend valves, pistons hitting valves bend valves.