Speed Offroad is one of the automotive sports that is done on the grevel circuit to take speed in laps of a certain lap. One of the factors that must be met to improve the machine's ability is the modification of the valve mechanism. The goal is to achieve maximum house power and torque. Other support that is done on the machine that is breathing polish intake and exhaust holes that aims to facilitate the flow of fuel and air into the combustion chamber, breathing camshaft, valve spring replacement, breathing polish manifold, head breathing, manifold breathing. Checking other components on the valve mechanism there are some parts that have exceeded the standard limit of rocker arm needs to do the replacement, seal valve, full gasket, camshaft. After the development overlapping valve mechanism, replacement of clutch, polish, ignition, suspension and engine power Suzukin Katana SJ410 there is an increase in torque 44.7 Nm and Power 22.8 Hp which previously had torque 41.1 Nm and power 20,1 Hp.