Ridgeyard 50cc Bike Bicycle Motorized 2 Stroke Cycle Petrol Gas Motor Black Engine Kit Set for Motorized Bicycle 26"/28" Bike 50cc Bike Bicycle Motorized 2 Stroke Cycle Motor Black Engine Kit Set Package Included: 1x 50cc 2 Stroke Engine Motor Kit (Bicycle Not Included) To start, move the choke lever to "on" position, hold in clutch, pedal the bike to get some speed, and then release the clutch gradually To stop, slow speed, disengage clutch and apply either original brake (if you didn't remove the original left handle brake To stop the engine, choke the carburetor completely with the lever on the carburetor. Alternatively, slow speed, hold in clutch and press the kill switch on twist-grip throttle.6. If you want to use your bicycle as a common bike, just disengage clutch, then press the silver button at the side of clutch, the motor will not be started.