§571.123. Standard No. 123; Motorcycle controls and displays. — Inbound Citations

(c) a service brake system where the brakes on at least the front and rear wheels are actuated by the operation of a single control. (If the rear wheel and the asymmetrical wheel are braked by the same brake system, this is regarded as the rear brake.)

Control means the part actuated directly by the rider in order to supply and regulate the energy required for braking the motorcycle.

Driver mass means the nominal mass of a driver that equals 75 kg (68 kg occupant mass plus 7kg of luggage mass).

Engine disconnected means when the engine is no longer internally connected to the driving wheel(s), i.e., the clutch is disengaged and/or the transmission is in neutral.

Gross vehicle mass means the maximum mass of the fully laden solo vehicle, based on its construction and design performances, as declared by the manufacturer.

Initial brake temperature means the temperature of the hottest brake before any brake application.

Laden means the gross vehicle mass.

Lightly loaded means mass in running order plus 15 kg for test equipment, or the laden condition, whichever is less. In the case of ABS tests on a low friction surface (paragraphs S6.9.4 to S6.9.7), the mass for test equipment is increased to 30 kg to account for outriggers.

Mass in running order means the sum of unladen vehicle mass and driver mass.

Peak braking coefficient or PBC means the measure of tire-to-road surface friction based on the maximum deceleration of a rolling tire.

Power-assisted braking system means a brake system in which the energy necessary to produce the braking force is supplied by the physical effort of the rider assisted by one or more energy supplying devices, for example vacuum assisted (with vacuum booster).

Secondary brake system means the second service brake system on a motorcycle equipped with a combined brake system.

Service brake system means a brake system which is used for slowing the motorcycle when in motion.

Sidecar means a one-wheeled vehicle that is attached to the side of a motorcycle.

Single brake system means a brake system which acts on only one axle.

Split service brake system or SSBS means a brake system that operates the brakes on all wheels, consisting of two or more subsystems actuated by a single control designed so that a single failure in any subsystem (such as a leakage type failure of a hydraulic subsystem) does not impair the operation of any other subsystem.

Stopping distance means the distance traveled by the motorcycle from the point the rider begins to actuate the brake control to the point at which the motorcycle reaches full stop. For tests where simultaneous actuation of two controls is specified, the distance traveled is taken from the point the first control is actuated.

Test speed means the motorcycle speed measured the moment the rider begins to actuate the brake control. For tests where simultaneous actuation of two controls is specified, the motorcycle speed is taken from the moment the first control is actuated.

Unladen vehicle mass means the nominal mass of a complete vehicle as determined by the following criteria:

(5) S5.1 and S5.2.1 of 49 CFR 571.123, in any case in which the modification necessitates the relocation of original equipment manufacturer's controls.