Motorcycle: Racers - WR/ WRTT, 1940 - 1951
Date: Sunday, October 31 @ 15:33:22 UTC
Topic: Motorcycle, Motorcycles, Motor Cycle
WR/ WRTT, 1940 - 1951
Harley-Davidson's racing mainstay of the 1940s, the side-valve WR, had the humblest of beginnings, evolving by degrees from the unpretentious Model D of 1929. Essentially, this was powered by little more than a pair of Ricardo heads grafted from the 21. leu in (346cc) single (which had almost the same bore diameter) onto a common crankcase. The machine developed rapidly year-on-year, becoming the Model R in 1932, at which time its hottest roadster derivative was the RLD Special Sport Solo.
Racing efforts at the time, both official and private, were concentrated on overhead valve engines, both singles and 45-inch twins. However, by 1933 the RLDE twin with magnesium alloy pistons was available from the factory by special order.
Two years later still, the Series R range included five models based on the familiar flathead "45", crowned by the lean and purposeful RLDR Competition Special - a snip at $322. For 1937, a Knucklehead-inspired restyle and a welter of engine improvements metamorphosed the R into the enduring Model W. Other than the change of prefix letter, the 45-inch range continued as before, now with the WLDR Competition Special at its head — a WR in all but name. Harley-Davidson put this right in 1941: the WLDR still existed, but now as a mere Special Sport Solo roadster. Taking its place as the hottest 45 was the plain WR, a race machine available only to special order. Initially, availability was poor—just 36 WRs were produced in 1941 — but both demand and supply picked up dramatically in the aftermath of war. A total of 292 were produced in 1948,
121 in 1949 and 23 in the last year of production. These purpose-built racing machines were, of course, very much stripped down compared to their roadster cousins
(the WR had not so much as a front mudguard, and later examples also benefited from a lightweight chrome-molybdenum steel chassis). The WRTT, produced as a specific model only late in the WR's career, retained the heavier roadster frame. Being a flat-track machine, the WR also had no brakes, while the road-racing TT machine was equipped with standard WL wheels and brakes — scarcely state-of-the-art stopping power. The WR's suspension was no more impressive, with old-fashioned girder front forks and a rigid rear end. For good measure, the gearbox, although available with close-ratio racing cogs, was hand-change. It may have been crude, and 40bhp from 45 inches was unimpressive. Yet this, and sheer weight of numbers, was enough to rival the much more sophisticated but sorely handicapped overhead-valve twins and overhead-camshaft singles from Europe. The brute toughness of the WRTT, in particular, made it a surprisingly capable "Class C" racer. This formula had first been introduced for roadster-based machines in the 1920s to reduce the spiralling cost of Class A and B factory specials.
For more than a decade, these outwardly primitive machines gave a good account of themselves on the race tracks of America — taking 19 out of 23 championship victories in 1948 alone. This was partly because they were rugged and dependable, and partly because the AMA was as eager then as it has been since to adjust the rules in favour of domestic hardware. In this case the AMA, which is the governing body of American motorcycle sport, greeted the arrival of fast European overhead-valve machines with a decree that said they would be limited to 500cc, while side-valves of 750cc were permitted. And guess who made the only flathead racers in the frame?
Engine: side valve 4-stroke V-twin
Capacity: 45.3cu in (742cc)
Transmission: 3- or 4-speed
Wheelbase: 60in (1,525mm)
Top speed: around 105mph (169kph)
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