The crankshaft of a typical in line four cylinder engine has 8 balance weights.
Camshaft in an engine is always mounted parallel to the crankshaft.
In a four stroke engine for each crank shaft revolution, the camshaft revolves one half turn.
A camshaft on a four stroke engine runs at 1/2 the crankshaft speed , the intake and exhaust valves opens once (each) for each two engine revolutions. In a two stroke engine, it is one to one.
The timing belt is attached to the camshaft pulley and timing belt drive pulley.
The motion of the cam is transferred to the valves through rocker arms.