The BMW R 45 was a mid-range motorcycle manufactured by BMW from 1978 to 1985. It was powered by a twin-cylinder boxer engine assisted by a five-speed transmission and a shaft final drive.
In 1981, the German motorcycle manufacturer released the BMW R 45, a motorcycle in its fourth consecutive production year. Compared to the previous model, the 1981 motorcycle was revised.
Some modifications included Nikasil-coated cylinders, making them more durable and lighter, a transistor ignition, a geared one plate to the clutch, making gear changes smoother, a larger oil pan, and better lubrication for the crankshaft.
Other modifications included a second interference pipe, the choke lever moved from the engine block to the left handlebar fitting, and a redesigned air filter with a plate filter and a black housing.
In the visual department, the motorcycle had standard fittings, such as a front fender mounted close to the wheel, a round headlight, a one-piece dual seat, side-mounted rear shocks, a two-into-two exhaust system with a silencer mounted on each side, a center stand, and multi-spoke aluminum wheels.
The 1981 BMW R 45 was powered by a 453cc four-stroke twin-cylinder air-cooled boxer engine mounted underneath the fuel tank, delivering an output power of 27 hp at 6,500 rpm and 38 Nm (28 lb-ft) torque at 5,500 rpm.