In 4-step fuel motor, piston and valve have a great influence on the performance and character of the machine, let alone combined with the magnitude of the compression ratio. The study was conducted using a 29/24 valve, a piston diameter of 55.25mm and a compression ratio of 15: 1. This study aims to determine and compare the performance of Jupiter 110 cc engine before and after bore up, changes in diameter valve and compression ratio in testing fuel, power, torque, and travel time. This research method using standard Jupiter motor that has been replaced carburettor and exhaust with motor bore up 130 cc with 29/24 valve diameter and 15: 1 compression ratio. Test method using dynotest test instrument by entering transmission, one tooth before last tooth and open throttle fully from rpm 5000 to touch limiter. The results obtained are graphs. The data obtained in using the dynotest is power and torque while the fuel consumption and travel time are tested separately. The results showed that by increasing the diameter of the piston and valve and then offset by enlargement of the compression ratio can increase the performance of the motor fuel is large enough. Value percentage increase in torque, power, fuel consumption is a comparison with jupiter 130 cc tune up. In the 110 cc motor tune up the maximum torque generated is 9.7 Nm compared to 14.65 Nm, maximum power 11.9 kW compared to 20.7 kW, fuel consumption 110 cc tune up 24.64 km / l compared to 130 cc tune up 15.55 km / l, and travel time 14.32 seconds compared to 10.13 seconds at 201 m.