As the crankshaft is subjected to complex bending shear and twisting loads, it needs to be well designed and manufactured in good quality material to withstand the stress. As these stresses may change in direction and magnitude as the crankshaft rotates. In the balancing of the crankshaft, it needs to consider both the static balancing and dynamic balancing. In design calculation of crankshaft kinematics of crank gear, indicator diagram, force acting on the crankshaft and torque acting to the major journal and crank pin are important. The influence of the forces due to inertia both the reciprocating and rotating masses must be taken into account as accurately as possible, especially for high speed. The engine is four cylinders, four-stroke engine, and compression ratio is 20. The maximum power output of the shaft is 70.4 kW at 3200 rpm. The crankpin diameter and length are 56 mm and 31 mm, the main journal diameter and length are 65 mm and 32 mm. The operating conditions of cranks gear elements characterized by the forces which appear in them at various engine duties.