TDPRO 125cc Engine 4 Stroke Motor Semi-Auto 3 Forward 1 Reverse Gear for ATV 4 Wheelers Tricycle This 125cc Semi-Auto Engine has reverse gear suitable for ATV UTV 4 Wheelers Speed complete racing engine, 3 forward 1 reverse gear Upgrade your stock 50cc to this 125cc monster, you can feel the power difference immediately See below description for more specifications and wiring