Front Fork (“FF”) of a motorcycle has some characteristics; spring force, damping force, stiffness and so on. They have great influence on the movement of a motorcycle. Under the present conditions, the settings of FF characteristics are tuned up through trial and error by rider's evaluation of driving, and so we need much time and cost. In this research, we model the detail of the inner structure of a FF, and calculate damping force. Then, we verify that calculated results correspond well with experimental ones. And we make a simulation model of a motorcycle considered the detail FF model by using mechanical analytical language, and it is verified that the simulation correspond with the experimental results. So, it is verified by simulation how the movements of a motorcycle be varied according to the different of FF characteristics. In conclusion, though limited in some running conditions, we have cleared the relation between the FF characteristics and the movement of a motorcycle. Now, the research enabled us to predict some characteristics of FF by simulation instead of them decided by trial and error.