Daring to be different
While its rivals stuck with the near-ubiquitous in-line DOHC four cylinder engine, Honda had a long-term investment in the V-4 layout, and refused to submit. But it came at a cost – a big cost.
The motorcycle
that was created to win the World Superbike Championship – and succeeded in 1988 and 1989 – the Honda RC30, was, after six years, getting a bit long in the tooth. By 1994, something was needed to stay with the likes of the Ducati 916, the Kawasaki ZX7-R and soon, the Suzuki GSXR-750. That something was the RC45, or the evolution of the RVF750 if you prefer.
Honda built just enough of these – 200 – in the 1994 (only) production year, to qualify for the championship, and over the next five years a handful more trickled out to keep the various teams around the world supplied. It took until 1997 for John Kocinski to achieve the Honda factory’s aim of wrestling the World Superbike Championship from Ducati, but the RC45 made a winning debut three years earlier at the 1994 Isle of Man TT when Steve Hislop, Phillip McCallen and Joey Dunlop gave the works-supplied UK Castrol Honda team a resounding clean sweep of the podium in the Formula One TT, followed later in the week by an identical result in the Senior TT. Indeed, with the only works squad in the event, Honda UK and the Castrol RC45s would dominate the TT for the next five years. Out in the colonies, Anthony Gobert gave the RC45 a dream debut at the wet Phillip Island round of the Australian Superbike Championship, and continued his form to become (at 19) the youngest-ever winner of the title after a season-long battle with the Kawasakis of Martin Craggill and Matthew Mladin. The following year, Kirk McCarthy took over the Winfield RC45 and won the title from Mladin. In the UK, the RC45 carried a price tag of £18,300, or about the same price as the Ducati 916SPS and Bimota SB7. That became $35,000 in Australia, but the promise of a works racer that was available to the public was very tempting for those sufficiently well-heeled to consider placing an order. The reality was somewhat different. While the race bikes were bedecked with exotic suspension, wheels and other fitments permitted under the formulae, the RC45 sold to the public was more prosaic. The front forks, for example, were similar to the CBR600 with 41mm tubes, which were on the puny side by the standards of the day. The front hoop was a 16 incher – specifically a 130/70ZR16 – that by 1994, was also somewhat passé, with the opposition all running a 17 inch front, and a curious choice given the rear tyre was a 190/50ZR17. Switchgear was sourced from the Honda CBR900. Indeed, the existence of the CBR900 Fireblade was somewhat of an embarrassment to Honda, as this relatively simple (and affordable) in-line four could give the RC45 a serious run for its money. The RC45 is inevitably compared to its forebear, the compact and nimble RC30, but in appearance at least, seems bigger all round. Whereas the RC30 perched its rider over the front, the riding position on the RC45 is more relaxed and contemporary. The seat height is 50mm lower, as is the centre of gravity, which was central to Honda’s aim to get the new machine to turn into corners with more precision and less rider effort. From the beginning of Honda’s V-4 series – the VF750S of 1972 – bore and stroke had been consistent at 70mm x 48.6 mm, but the RC45 broke with tradition with a bore of 72mm and a stroke of 46mm. As on the RC30, titanium connecting rods were
“With the only works squad in the event, Honda UK and the Castrol RC45s would dominate the TT for the next five years.
”Chassis-wise, the RC45’s twin-spar aluminium frame used thinner wall frame members than the RC30, supposedly to engineer more flex into the unit, although the external dimensions were larger.”
used, but the cylinder bores were now of what Honda called ‘metal composite’ – a ceramic-blended aluminium that could be rebored if required. The process saved an impressive 1.4kg. In the cylinder head, valve angles were reduced by a total of eight degrees. The signature gear-driven camshafts were retained in the RC45, but moved from the centre to the right side of the engine, which permitted a shorter crankshaft – and more weight saving – plus a straighter passage for the inlet tracts. The most visible change between the 30 and the 45 was in the use of a radical fuel injection system that had been developed on the exotic oval piston NR750. This used 46mm throttle bodies instead of the 38mm Keihin carbs with a total of seven sensors to deal with mixture control. Chassis-wise, the RC45’s twin-spar aluminium frame used thinner wall frame members than the RC30, supposedly to engineer more flex into the unit, although the external dimensions were larger. The frame itself was built around a large diameter castalloy steering head. Although the new machine looked larger, the wheelbase was only 5mm longer, courtesy of a longer swinging arm. The swinging arm itself was once again the Elf-patent single-sided unit, controlled by a fully-adjustable gas-charged shock absorber that owed much to the company’s successful motocrossers. At the steering end, the forks provided 24.5 mm trail and 92mm rake. While the RC30 used hand-laid fibreglass for the fairing, the RC45’s bodywork was in plastic. More weight saving. With 120 hp at 12,000 rpm on tap, the standard RC45 was hardly a slouch, but an extra 30 hp was available to those who wanted to go serious racing, and could afford it. And make no mistake, some serious coin was required to make the RC45 competitive. For this reason, few privateer teams opted for the Honda, when there were several choices available from rival manufacturers at a substantially lower cost. The genuine HRC kit parts included bodywork, wheels, front forks, rear shock and linkage, clutch, complete swinging arm, engine covers in magnesium, and sundry smaller items. Price? Best not to ask.
Early tests of the RC45 gave journalists plenty to think about, with the inevitable comparison to the RC30. Most agreed that the most endearing characteristic was the glorious sound – Formula One on two wheels. The snarl emanates from beneath the tank with vast amounts of air rushing in, although the tunnels running from the front of the fairing to the fuel tank top are largely cosmetic. The close ratio gearbox made it a chore around town; the tall first gear requiring a handful of revs in order to pull away cleanly, and judicious use of the gearbox in traffic. But the RC45 was hardly designed with traffic in mind, except perhaps, lapped traffic. Low, steeply angled handlebars bars were also uncomfortable around town but perfect for the open road. The engine was also somewhat cold blooded and needed warming up so the temp gauge showed at least 70 degrees before riding off. The choke knob mounted on the left fairing inner is actually nothing more than a fast idle lever, as the extra richness a cold motor demands is catered for by the Programmed Fuel Injection system (PGM-FI) lifted from Honda’s technology showcase, the NR750. This is fed information from seven sensors measuring critical parameters such as intake air temperature, barometric pressures, and engine rpm, and then supplies the right quantity of fuel ignited by a spark at the optimum moment.