Beschreibung:

Offered for sale following a painstaking 10-year restoration by its German engineer owner, this ultra-rare Münch-URS is one of two machines built by the Münch factory for the 1970 Grand Prix season and ridden by Ferdinand Kaczor and Karl Hoppe. John Blanchard, Münch-URS Team Manager, has confirmed to Bonhams that the frame of this machine is indeed one of the two used by Kaczor and Hoppe in 1970. Freshly rebuilt and in running condition, this Münch-URS was one of the star attractions at Mallory Park’s Bonhams-sponsored 50th Anniversary International Post-TT meeting on 10-11th June. Although the precious machine did not take to the track, it never failed to gather an appreciative audience whenever it was started, the crowds delighting in the distinctive, ear-splitting bark from the four megaphone exhausts. (This Münch-URS has since been track-tested by Alan Cathcart for a forthcoming edition of Classic Racer magazine). A quantity of assorted spares and all the necessary special tools to work on the engine are included in the sale, together with a comprehensive album of photographs recording the restoration in detail. The Münch factory’s Grand Prix solo project resulted from an alliance with two-times World Sidecar Champion, Helmut Fath, whose second world title in 1968 had been gained riding a machine of his own design and manufacture. Fath’s URS sidecar outfit was powered by an advanced 500cc four-cylinder engine that seemed tailor-made to challenge the might of MV Agusta in Grand Prix racing’s premier solo class. Indeed, Münch was not the first to come to this conclusion - a couple of years earlier, Colin Seeley had built an URS-powered solo for John Blanchard to ride, on which the latter finished 4th at the 1967 Ulster Grand Prix. During a lengthy convalescence – the result of a serious accident in 1961 that claimed the life of his passenger, Alfred Wohlgemuth – Fath had spent his time tuning BMW engines for his fellow sidecar racers. He planned to return to competition in 1963 but BMW refused to supply him with engines, a snub that Fath determined would not go unpunished. With assistance from Dr Peter Kuhn of Heidelberg University and fellow racer/engineer Horst Owesle, the project took shape in Fath’s forest workshop outside the town of Ursenbach, from which it took its name – URS. Although similar in outward appearance to the MV and Gilera fours, the eight-valve URS motor incorporated several unusual design features, not the least being its two separate crankshafts (set at 90 degrees) driving a common countershaft that had the contact-breakers for the twin-plug ignition mounted on its right-hand end. Drive to the Schafleitner six-speed gearbox was taken - via large diameter pinions - from the countershaft, which also drove the twin overhead camshafts by means of a single-row chain running behind the cylinders, a move that helped keep engine width to a minimum. Kuhn’s expertise and the use of special valve springs enabled the URS to rev at up to 15,000rpm, an exceptional figure for a 500cc four with two relatively large valves per cylinder. Bosch fuel injection was fitted, the first successful use of such a system on a racing motorcycle, while in a later development aimed at improving gas flow, Kuhn specified a second set of ‘air only’ down-draught inlet ports. Japanese Keihin carburettors and transistorised ignition were fitted subsequently as development progressed. Although larger, heavier and possessing a higher centre of gravity than the rival BMW flat twin, the higher-revving URS four made 84-88bhp compared to the BMW’s 65-70, which would prove more than enough to make up for those apparent handicaps. Only a handful of complete URS engines was ever made; somewhat unusually, Fath chose to give them names rather than numbers – the 1968 Championship-winning engine being known as ‘Gustav’. After a shakedown debut season in 1967, Helmut Fath duly gained his revenge the following year, beating BMW-mounted Johann Attenberge