1993 BMW K73
|Also called||The Flying Brick|
|Engine||Longitudinal DOHC I3, 750 cc (46 cu in)|
|Bore / stroke||67 mm × 70 mm (2.6 in × 2.8 in)|
|Top speed||131 mph (211 km/h)|
|Power||75 hp (56 kW) @ 8000 rpm|
|Torque||50 lb·ft (68 N·m) @ 6000 rpm|
|Transmission||5-speed foot shift, shaft drive|
|Frame type||Tubular steel, open cradle with engine as stressed member|
|Suspension||Telescopic forks, single-sided swingarm|
|Brakes||Dual front discs and single rear disc, or rear drum|
|Wheelbase||59.7 in (152 cm)|
|Dimensions||L: 87.4 in (222 cm)
W: 35.4 in (90 cm)
H: 51.2 in (130 cm)
|Seat height||31.9 in (81 cm)29.9 in (76 cm) (low seat)|
|Weight||505 lb (229 kg) (dry)
536 lb (243 kg) (wet)
|Fuel capacity||5.54 US gal (21.0 l)|
|Fuel consumption||59 mpg-US (4.0 l/100 km)|
Various models of the K75 were produced:
The S and RT versions have a rear disc brake and 17 inch rear wheels, whereas the others have a single leading shoe drum brake and 18 inch rear wheels. A stiffer "anti-dive" front suspension was added to the S and RT models. The later RT versions had an adjustable windshield that could be raised or lowered. Some taller riders complained of wind buffeting with the smaller S model stock windscreens.
All K75 models share the same drivetrain. They are powered by a 740 cc liquid-cooled inline three-cylinder engine with Bosch fuel injection. The US EPA specific engine produce 68 hp (51 kW) while all others produce 75 hp (56 kW). They have a five-speed transmission with a dry clutch and a shaft-driven final drive. The engine is oriented longitudinally and horizontally to lower the center of gravity and allow the most efficient power transfer to the shaft drive.
The K-series lineup, including the K75 and K100, were not just new models; these designs were radical departures from almost every aspect of previous BMW offerings. The K-bikes introduced new technology and refinement to a premium brand. At the time, BMW and Harley-Davidson were the only major manufactures that did not offer liquid-cooled engines. Competing brands, notably of Japanese manufacture, were touting the superiority of their liquid-cooled engines and had introduced low maintenance shaft-drive technology in a growing number of their models.
The K-series offered refinements such as computer-controlled fuel injection, all stainless steel exhaust, rust-free aluminum fuel tank, anti-lock brakes on later models, mono-lever in the rear and single shock absorber, adjustable headlight, high capacity 460 watt alternator, electrical accessory plug-in, and self-canceling signal lights. The engine design had excellent vibration isolation with an internal counter rotating shaft. Two different forks manufacturers were used: Showa with an outer upper tube diameter of 1.612 in (41 mm) and Fichtel and Sachs measuring 1.627 in (41 mm).
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