Description
BMW 1987 MKM 4-valve racer
This 4-valve racer convinces with simple elegance. Perfect proportions and shapes, the whole bike is well designed and clean.
The former racer Uli Völkl original BMW R 100 RS already had 4-valve cylinder heads by Krauser, 40mm Dell ' Orto carburettors with K & N air filter, and equipped with a larger magnesium oil sump and nicely shaped aluminium fuel tank by Fallert.
Silencers Hoske-style round out the whole, also acoustically.
The frame was strengtened by Völkl for racing purpose and he adapted a cantilever swing arm. From the Fallert foot rests only the levers were left.
New stainless steel foot rests have been turned and mounted relatively far back. From a R 100 R Classic came the reinforced and stiffened front fork, a 10 mm thick stainless steel laser-cut stabilizer brace reinforced the front.
The handlebar extensions have been removed on the upper fork bridge, because the 4V racer wants to be directed by Tomasselli handlebars.
Not only the handlebars are Italian, but also the lavishly customized fairings of the type Ducati 750 SS.
The conclusion is a shorter rear frame, equipped with an aluminium seat and a custom built upholstery.
Very British: the painting in dark Racing Green.
Wire spoked aluminium wheels are 18-inch Akront, adapted with the tyre sizes 110 front and 150 back.
A double disc brake by Wiwo on the front wheel, controlled by Steelflex hoses, almost reach the present standard, especially given the low weight of under 200 kg.
Easy game for the approximately 90 HP 4V-Boxer.
Technical data:
Performance: 87 HP (64 KW) at 6800 RPM maximum torque 85Nm at 5500 RPM
Motor: Basic R 100 RS. Four-stroke two-cylinder boxer engine, air cooled. Four valves per cylinder (type Krauser). Bore x stroke 94,0 x 70.6 mm. displacement 980 cc. Two Dell'Orto carburettors, 40 mm with K & N air filters. Magnesium oil sump from Fallert. Stainless steel Exhaust pipes, 40 mm, with silencers in the Hoske style. Electric and kick start. Five-speed gearbox, drive-shaft.
Chassis: tubular steel frame type R 100 RS with stabilizer bars and shorter tail. Fork type R 100 R modified. Rear steel tube cantilever swing arm with central spring (Monoshock). Wire spoked wheels, tyres front 110/80-18 rear 150/70-18. Wiwo double disk front brakes 285 mm, rear drum brake type R 100 RS. Wheelbase 1450 mm, steering head angle 62 degrees. Seat height approximately 780 mm. Fallert-Aluminium fuel tank, contents more than 20 litres. Weight 190 kg without fuel.
Source: motorcycle Magazine Special Edition No. 44. Jan. Feb. 2013