Legislation often distorts the market. When learner riders were restricted to 250cc machines in the UK in 1960, at the height of the café racer era, suddenly every young gun wanted the fastest 250 available.
No manufacturer captured the mood better than Royal Enfield, with its Continental GT, launched in 1964. A coffee bar cowboy’s dream, the GT came from the factory with clip-ons and rear sets, a big red racing tank and a Perspex fly screen mounted on the polished top yoke. Even the front brake was adorned with ‘bacon slicers’, the highly fashionable alloy discs that were supposed to keep the brake drum cool. With a 5-speed gearbox and over 20bhp, Royal Enfield couldn’t keep up with demand.
By the time the company ceased production in 1967, others had woken up. The BSA Barracuda and Starfire 250s delivered a claimed output of 24-26bhp (enough to reach 80mph) but were later detuned in the interests of reliability. The styling mimicked the company’s 650 twins, with a racing hump to the dualseat and a sculpted tank, so the learner rider could identify with the bigger, more powerful models.
The British bikes were overtaken by the growing invasion from Japan; four-stroke twins from Honda and exhilarating 2-strokes from Suzuki, Yamaha and Kawasaki, who even provided a 250 with three cylinders and three shiny chrome exhausts for those who really wanted to show off. Top speeds were lifted into the 90+ category but nobody had yet cracked the elusive ‘ton’.
Ducati’s glamorous 250 Desmo fought a rearguard action for the 4-stroke single, with its loud megaphone exhaust, bevel-driven overhead cam and huge Dellorto carb. The styling looked the part, too, with clip-on handlebars and a vivid yellow racing tank, but Ducatis were way too expensive for most learners and always a rare sight in the UK.
The power race continued between the Japanese factories, culminating in Yamaha’s RD250LC in 1980, which raised the bar to a claimed 35.5bhp and an official top speed of 98mph. Just as Yamaha had revised its twin-cylinder racers from air-cooling to liquid-cooling (LC) in the search for greater power combined with reliability, the same benefits were claimed for the road bikes.
In 1983, UK learners were restricted to 125cc bikes. Whether this was the direct result of the RD250LC has been debated but it certainly fuels the legend that has grown up around this model. When the original 250 limit was set, a typical British 250 would only have developed around 12-15bhp so legislators did not foresee learners approaching 100mph!
In the Japanese home market, for many years the tests for smaller bikes (250 and 400cc classes) have been much easier to pass than for bigger ones. This has led to a succession of incredibly sophisticated and exotic 250 and 400 models to satisfy demand from a large pool of riders unable or unwilling to progress to larger bikes.
One of the most popular is Honda’s CBR250RR four from the 1990s which revs to 19,000 rpm. The next time you see a 1960s Honda Grand Prix replica at an event, take a closer look; if it’s got a radiator then it’s probably one of these engines – they certainly make all the right noises.