(1) Steering: The front wheel and the handlebar cooperate to control the direction of the motorcycle. The handlebar is installed on the upper link plate. When the handlebar rotates around the steering column, the upper and lower link plates rotate accordingly, and the front wheel is driven to rotate left and right through the front shock absorber. The right end of the handlebar is equipped with a throttle handle for controlling the opening of the carburetor throttle valve and a brake lever for controlling the front wheel brake; the left end is equipped with a grip and handle for controlling the clutch. Rearview mirrors and various electrical switches are also installed at the left and right ends of the handlebar. The handle and brake handle control the front wheel brake, clutch and carburetor through steel cables. There are different specifications of the steel cable, 1×19 outer diameter ∮2～∮2.5mm single strand steel wire rope for brake and clutch, and 1×7 outer diameter ∮1.2～∮1.5mm single strand steel wire rope for carburetor.
(2) Braking: Generally, the front wheel braking is controlled by the hand brake lever, and the rear wheel braking is completed by stepping on the brake pedal. There are two types of brake devices for motorcycles: mechanical drum brakes and hydraulic disc brakes. The structure of the drum brake is similar to that of automobiles and tractors. The brake shoes are formed by die-casting aluminum alloy, and friction brake pads are glued on them. The brake arm rotates the brake cam and pushes the brake shoes to achieve the purpose of braking.
The brake consists of an oil tank, a plunger valve oil pump (all on the handlebar), hydraulic oil pipes, brake calipers, brake discs, etc. The brake is staggered and fixed together with the front fork guide, which is the fixed part of the brake device. The brake disc is fixed to the wheel and rotates with the wheel. When braking, hold the brake handle firmly, the plunger valve moves, pushing the hydraulic oil into the two cylinders of the brake caliper along the hydraulic oil pipe. Under the action of pressure oil, the oil cylinder pushes the friction plate to clamp the brake disc tightly from both sides, which produces a great friction resistance, forcing the wheels to stop rotating. When the brake lever is released, the pressure in the hydraulic oil circuit drops rapidly, and the oil cylinder drives the friction plate to return to its original position to release the brake.