Cycle News - Archive Issues - 2000's

proved totally unrideable, falling into the latter category surely is the Dryvtech 2x2x2, a two-wheel drive, two-wheel steer, two-stroke enduro bike built back in 1990 and now residing in Britain. Visitors to the Donington Park race circuit for the British GP there later this year can view the Dryvtech in the circuit museum amid the exotic extravaganza of Formula One racing cars down the years - alongside an example of the Drysdale 750-V-eight bike engine powering the Bruiser prototype. But the Dryvtech, though ingenious, was just a taster for Drysdale's next technical tour de force - the design and construction of his own 750-V-eight sportbike. When I tested the barely completed eight-cylinder bike at the Calder Park test track in June of 1997, my ride on a machine bristling with potentia I provided a hands-on appreciation of the Drysdale team's drive in making such a complex project achieve reality, as well as underlining the probable potential for limited-production manufacture of spin-off versions. Almost five years down the road, after competing with a race version of the 750V-eight in Australian Formula Xtreme events, to provide ongoing R&D interspersed by lan's need to earn the funds required to fuel the next stage of V -eight development by doing other, more arcane, engineering work - including, for example, acting as technical consultant to a couple of Chinese motorcycle factories - as well as sourcing the backing to develop his own 990cc V-eight MotoGP race project, the final specification of the Drysdale V-eight Bruiser road models has crystallized. With Cruisers and Naked roadsters dominating sales charts around the world, it was almost inevitable that the Drysdale V-eight engine would end up powering such a bike, as Drysdale explains. "We had lots of response from all over the world for the 750-V-eight sportbike," he says, "but literally dozens of potential customers, mostly professional blokes in their' 50s in the USA and Britain as well as Australia, told me they'd like to place an order, but only for a more chilled-out version with a less uncompromising riding position. One of them rode the superbike and said it was all very well and he really liked the engine, but at 50 years of age he didn't really need to visit a chiropractor for a week as the payback for going for a Sundaymorning ride. Several of them also sa id that if they were going to spend around $80,000 [Australian dollars, roughly $47,000 US] on a motorcycle, it had to have a passenger seat so they could take their wife on the back - else they wouldn't get clearance to buy it in the first place! So, that's what I've developed - basically the same mechanical package as the 750-V-eight but with a 1000cc motor, a twin-shock chassis with a more laid-back riding position, and facilities for a pillion." "We'll be building two distinct models, on both of which Duncan Harrington did the styling - the same guy who designed the superbike for us," continues Drysdale. "One is the Bruiser, with an 8-into-2 exhaust system, six-speed gearbox, cast wheels, flat bars, semi-rearsets and more aggressive styling, aimed at out-Monstering the V-twin Ducati, but with a V-eight engine. The other model is the Cruiser, which will feature wire wheels, eight separate exhaust silencers, a five-speed gearbox, forward-mounted footpegs and pulledback handlebars, and though both models will be similar mechanically, the fact we're adopting fuel injection as standard means we can remap the Cruiser to give more relaxed performance - though still with the ability to get up and go when called upon. Not surprisingly, we've had a lot of interest for these models from the USA and Japan, as well as Australia - we had three customers sign up even before I built the first prototype, and I'm almost at the point where I can start making them in batches of six, which would bring significant cost benefits, and thus lower the price for what, after all. will still be a handbuilt motorcycle." The Bruiser prototype, which Drysdale recently allowed me to ride, uses an all-new, twin-shock, low-rider version of the 750-V8 Superbike's tubular-steel spaceframe chassis, with a 700mm seat height and more kickedout geometry, including a slightly longer 1430mm wheelbase and 26degree fork angle - though this can be adjusted to suit individual taste, via eccentric inserts. The TIG-welded tubular-steel spaceframe is built from ERW mild steel (less prone to stress fractures than chrome-moly, says Ian), with Ducati-style triangulation on the side spars and a Kawasaki ZZR1100 alloy swingarm, and the engine forming only a semi-stressed underslung component. R1 Yamaha forks, wheels and brakes are used on the prototype, but by its very nature the Drysdale V8 Bruiser is a bespoke bike, leaVing each customer to determine its exact specification - though in keeping with such an expensive piece of high-tech hardware, Drysdale is encouraging early customers to opt for Ohlins/WP upside-down forks and Brembo brakes, to accompany the multi-adjustable high-end Penske twin shocks used on the prototype. In spite of the twin frontal water radiators used on the Bruiser, replacing the under-seat Urad" of the 750-V-8 Superbike, and the meaty mass of that V-eight motor, Drysdale says he's held the weight of the finished Bruiser down to just 453.2 pounds dry, with only a slight rearward weight bias - pretty remarkable for an eight-cylinder motorcycle. "We may downsize the radiator area on future customer bikes," he says, "but with the lower one mounted behind the exhausts, I decided to play safe for hot-weather use." cue I • The Drysdale V-S Bruiser Is definitely a point-and-shoot machine, as this photo shows. Even at this little of a lean angle, the right-side pipe Is almost touching down. For those in need of a refresher course in the engine architecture of the only V-eight motorcycle in the world you can actually purchase with a dedicated motor (as opposed to a Boss Hoss-style Chevrolet V-eight automotive transplant), the Drysdale uses as large a number of Yamaha proprietary parts as possible, mainly to allow customers around the world to source spares easily - a policy reflecting the enthusiastic support which Yamaha Australia has given to the project from the start. So the 750-V-eight motor in the prototype uses two FZR400R 16valve cylinder heads mounted on a horizontally split crankcase, specially designed by Drysdale (himself a qualified draftsman) to incorporate the cylinder blocks in the upper crankcase half, for added rigidity. The two banks of cylinders are set at 90 degrees to each other for perfect primary balance, and with the central chain camshaft drive of the Yamaha slantblock engine form~t retained, Drysdale has been able to reverse the camshafts and rotate them backward on the rear set of cylinders, while those on the front bank, as well as the crankshaft, all run forward. Yamaha parts retained on the 56 x 38mm 749cc engine include connecting rods and pistons (eight of each), all 32 tiny valves n • _ S • APRIL 3, 2002 37

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