Round·up
ROUND·UP
JOE PARKHURST
YVON DUHAMEL, the fiery French-Canadian (as if you didn't know), took a trip to Europe and won the Champion Spark Plug-sponsored Formula 750 Championship on the Dutch TT course in Assen, Holland. The win was long overdue; it has been nearly three years since DuHamel has taken a big one. All the leading European 750 defenders were there, but Yvon and fellow Kawasaki team man Hurley Wilvert caused most of the excitement.
In the first race DuHamel led, but Suzuki's Barry Sheene was soon joined at the front by Barry Ditchburn (Kawasaki). Sheene had prob lems with his exhaust pipe and Ditchburn ran out of gas. Yamaha's Agostini and Ce cotto were never in conten tion after Ago crashed. John Boote and Jack Findlay, both riding Yamahas, were 2nd and 3rd.
I YCLE WORLD's show is set for April 1st through the 4th, 1976, in case you were wondering. It will be at the Los Angeles Sports Arena again, of course. It will be the biggest and best again, of course. If you want to see some other shows that feature bikes and custom cars and vans, Gary Canning, our partner in putting the CW show together, also has the following California extravaganzas coming up: Santa Barbara, December 5th; Lancaster, January 16th, 1976; San Bernardino, February 13th; San Diego, March 19th; Bakersfield, May 14th; and Ventura, June 4th. Canning is king of the show circuit as you can see.
In the second heat the crowd went wild when local boy Wil Hartog led from the start. Sheene passed him, set ting a new lap record, then retired with mechanical prob lems. DitchbUrn pulled out also, then Wilvert took the lead. DuHamel and Suzuki rider John Newbold caught Hurley when he stopped for gas. The three were joined at the front by Findlay and Dutchman Boet van Dulman. It looked as though Wilvert had it bagged when he overcooked it at a hairpin, letting DuHamel and Newbold take over. Wilvert finished 3rd to them.
Sheene, who had just barely recovered from his awful crash at Daytona early in 1975, had been sidelined through most of the season. He gave Suzuki his best at the Dutch TT when he thoroughly blew off Agostini, and a week later at the Belgian Grand Prix when he set an absolute lap record for bikes at 135.75 mph before having to retire. The next week he went to Silverstone in England and won the British round of the Formula 750 Championship. He also won every race he entered at the John Player Grand Prix at Silverstone.
INNOVATIVE engineering is not quite dead in England, as some would have you believe. Although the troubles of Norton Villiers Triumph are by no means over, and their survival is still an unanswered question, the pickets surrounding the Wolverhampton Norton factory formed an interesting background for a recent press conference. The press was being shown one of the secret projects on which NVT had been working.
The project in question was the SPX500, co-designed by Bernard Hooper and John Favill. They also hold the patent rights that have now been surrendered by NVT. The bike was shown to the press while the official liquidator took over the NVT factory, so hopes of ever seeing it reach production by NVT seem slim.
Hooper, former NVT chief engineer, and inventor of the Isolastic suspension used on modern Nortons, said: “The original reasoning behind the design was the need to have a new engine which could be manufactured at savings in cost compared with existing four-stroke and Wankel engines.” Favill, co-designer of the SP, or stepped piston engine, was for many years responsible for exhaust and noise emission design at NVT.
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The SP project was dropped by NVT chairman Dennis Poore after he opted for the use of a Wankel engine. It has since received considerable financial support from the National Research Development Corp. Now, following NVT’s decision to liquidate the Wolverhampton plant and move all production to the old BSA factory at Small Heath, Birmingham, some see the prototype as the key to the future.
The SP is actually a new concept of an old idea that goes back to the early days of the British industry when Dunelt made a 500cc singlecylinder two-stroke with a stepped or dual-diameter piston. (Hooper is a leading authority on two-strokes and during his long service with Villiers —that ended six months ago—designed the Starmaker engine). The new engine, however, is a Twin with a 180-degree crankshaft. The stepped piston arrangement uses cross-flow ports opened and closed by the piston. There are no transfer ports. It is claimed to give cleaner carburetion by allowing fresh charges of fuel and air into the cylinders without having to use the crankcase as a pump. Each piston actually helps the others. Since the complete firing cycle is within the cylinders, the bottom end is isolated from the top as in a four-stroke. Twin carburetors are used with reed-valve induction, but plans are being made for a fuel-injected model up to 750cc.
The engine is rubbermounted and uses electric starting. A Norton gearbox is used on the prototype; production versions will use an integral five-speed unit. Pressed steel was utilized for the prototype frame, but a tubular chassis will be employed later. The fiberglass tank is a dummy. Shortened Norton forks are used, giving it a lower and more compact appearance. The styling seems to be more Italian than English. The designers claim that performance is competitive.
Fitted with a catalytic muffler and running on leadfree fuel, the 500cc version is said to be able to achieve 109 mph. The SPX500 weighs a shocking 391 lb. It delivers around 70 mpg. With a lighter overall weight and fuel injection, both performance and mileage should improve considerably.
The 750cc version is expected to reach 126 mph and deliver about 65 miles to the gallon. I expect that it will vibrate something awful, as well.
It is planned that the SPs will compete with the Japanese bikes. Development continues and it is anticipated that production will not begin for at least one year. I’m grateful to my old friend Peter Howdle at Motor Cycle News for the information.
OTO GUZZI is now installing a new safety brake system on all V-Twins produced at its Mandello del Lario plant in Italy. The 750 Sport, 850T Le Mans and California, and the new 1000 Automatic, all have a system designed by Lino Tonti, Guzzi’s famous designer. Basically it works like this: application of the righthandside brake pedal works one of the two front discs and the rear disc. The right-hand brake lever on the handlebar in the conventional location operates an additional front disc. Guzzi claims braking distance is reduced by 20 percent using the system properly.
The front disc operated by the foot brake receives a higher ratio of hydraulic pressure, so the third disc is considered to be an emergency unit.
Incidentally, Guzzi is preparing scaled down versions of its 350 and 500 V-Twins, as well as a single overhead cam four-cylinder 125. They were shown at the Milan show in November, so we expect to have photos for the next issue. The 850 Le Mans Guzzi mentioned above will also be introduced in Milan. It will have a fairing and spoked alloy wheels as standard equipment.
Ducati, Italy’s other superbike builder, will soon show a new 900cc Super Sport Twin that looks like the desmodromic winner of this year’s 24-hour Barcelona race. It is supposed to be able to reach speeds in excess of 135 mph in road trim and do the quarter-mile in under 12 seconds.
A LOT of technical inno vations appeared on motocross Grand Prix ma chinery in Europe this year. An example was the reed cage on Arne Kring's factory Husky that breathed directly into the crankcase, providing a full 180 degrees of intake. Jim Pomeroy used what ap peared to be shortened front forks on the rear of his fac tory Bultaco. The Bultaco rear suspension looks to have a lot in common with that of the New Harley-Davidson MXer (see CYCLE WORLD, Sept.
