Aussie V8 Superbike
AUSSIE V8 SUPERBIKE
ROUNDUP
DON'T LOOK NOW, BUT those kooky Australians are at it again, this time with a V-Eight sportbike! This newest Down Under wonderhot on the heels of the spacey Hunwick Hallam V-Twin-is the brainchild of Ian Drysdale, a 38-year-old Melbournebased design engineer. It uses a couple of Yamaha 400 cylin der heads mounted atop a common crankcase to form a 749cc V-Eight streetbike with 160-bhp potential. "I wanted to build a road legal factory racer-the highest performance motorcycle that could be ridden to the store for a loaf of bread," says Drys dale, who along with a small team of co-workers has poured literally thousands of man hours and bucketsful of money into the project over the past three years.
Centerpiece of the Drysdale 750-V8 Superbike is, of course, its unlikely lump of a motor, which uses the afore mentioned FZR400 top-ends, an FZR 1000 oil pump and clutch, a YZF75O gearset and a Kawasaki ZX-1 1 waterpump. "My aim was to build a unique machine, but with worldwide parts availability through the use of mainly Japanese compo nents in crucial areas," Drys dale says. "Setting up an inter national spares distribution for such a unique bike would have been a major headache."
Complex but extremely com pact, the 56 x 38mm V-Eight appears quite tall-but that's an optical illusion caused by the fact that, side-to-side, the en gine is extremely narrow. Cast locally in high-tensile alloy, the design is unusual in that the cylinder blocks are combined with the upper half of the hori zontally split cases for added strength and to reduce distor tion under heat treatment. The two banks of cylinders are set at 90 degrees to each other, though Drysdale admits he'd have preferred to go for a wider cylinder angle. "If I'd had a free hand, i'd have gone for 100 or even 105 degrees, to leave more space between the cylin ders for carbs or fuel injectionthere's no real vibration prob lem `til you reach 110 degrees of cylinder angle. But I'm happy with the 90-degree con figuration, which gives perfect primary balance," he says.
Tying everything together is a crankshaft that started life as a solid billet weighing 100 pounds. It now weighs just 12 pounds (contributing to a re markably low engine weight of 145 pounds complete), and has six main bearings with four crank throws, each with two big-end bearings, all plain. Both FZR400 heads have stock Yamaha cams and valves (four per cylinder), though the com bustion chambers have been re shaped to reduce their volume in order to restore some of the compression ratio lost with the 750-V8's 38mm stroke, com pared to 40.5mm stock. Carbu retion is provided at present by eight 32mm Mikuni CV carbs fed by a fuel pump, though an EFI system will eventually be fitted-it's no coincidence that MoTec, Australia's world-class engine-management house, is literally just up the road from Drysdale's Melbourne base. Radiator for the liquid-cooled engine is located under the seat, a la the Britten V-I 000 and Saxon Triumph, soon to be supplemented by a pair of fans. Redline is set at 17,000 rpmand, yeah, you better believe those spaghetti-bend 4-2-1 exhausts let loose with a posi tively carnal howl. The Drysdale Motorcycle Company (P.O. Box 285, Dan denong, Victoria, Australia 3175) hopes to be up and runfling by the end of 1997, hand assembling no more than 10 750-V8s per year. Interested? Bring $47,750 American-and your earplugs. -Alan Cathcart
