Is There A Ring-Ding In Your Future?
Is there a ring-ding in your future?
RONDUP
STEVE ANDERSON
THE WAR OF THE ENGINES WOULD SEEM TO BE OVER. THE four-stroke piston engine controls the American streetbike market, is used in more and more dirt bikes, and is gaining popularity even in Japan, where two-strokes have a long tradition. Looking at that success, you could only assume that the average motorcycle 10 years from now will be four-stroke powered.
But maybe not. New technology from the most unlikely of places may lead to a two-stroke revival.
And we mean unlikely: Any two-stroke comeback will be fueled by developments made by automobile companies that are seriously considering two-strokes for use in future economy cars. Of course, these would not be the short-lived ring-dingers of the past; any new automotive two-stroke would be a refined powerplant indeed.
This perking of automobile-company interest began a few years ago when a small Australian R&D firm, the Orbital Engine Co., demonstrated a modified Suzuki marine engine to American automakers. Unique to this engine were Orbital’s patented fuel injectors, which blew a combination of fresh air and fuel directly into the cylinder after the exhaust ports had been covered by the pistons during the compression process, thereby preventing the escape of unburned mixture out the exhaust. Emissions were lowered and fuel economy was raised compared to conventional two-strokes. Orbital further refined the engine with cleverly sealed and lubricated bearings that kept most oil out of the incoming charge, further improving emissions and engine cleanliness.
Most important of all, the engine fitted with these features was exceptionally light and inexpensive to build, particularly the clever injectors; overall, compared to a
four-stroke, the car companies estimated they could save several hundred dollars per engine. A car powered by such an engine might sell for $ 1000 less, all while offering improved performance.
The Orbital demonstration engine was the catalyst for large research projects at several automakers, research that has increasingly convinced these companies that two-strokes can be cured of any bad habits, and have some inherent advantages in simplicity and light weight over four-strokes of similar power. If all goes well, a car company may have a new-generation two-stroke engine in production by the 1992 model year.
If that comes to pass, the same technology would obviously allow motorcycle two-strokes to be brought back to American streets. These new two-strokes would have broader powerbands than their predecessors, be more durable, and run more cleanly across the entire powerband. They’d be no more likely to foul plugs than a four-stroke.
As an example of what might come to pass, imagine, say, a 1993 Yamaha or Suzuki 600cc four-cylinder sportbike. This two-stroke, hidden away inside a fairing that looks little different than that of Honda’s 1993 Hurricane equivalent, might make 100 horsepower, allow the motorcycle it powered to weigh 10 percent less than that four-stroke Honda, and sell for $300 less. Would you be interested in such a bike?
Of course, right now, this is just speculation; in the end, four-strokes may remain the only choice for American streetbikes. But that’s no longer mandatory. And maybe, just maybe, the 1990s will see the renaissance of the two-stroke engine.
BMW K75 "low rider"
BMW has just introduced a K75 designed for those short of inseam. Called simply the K75, the new model has a claimed seat height ofjust 29.9 inches, which is two inches lower than that of the K75C or K75S. Finished in white with red pinstripes, the K75 has a price of $6750.
Harley's new race V-Twin
A t a press conference in Daytona Beach, Harley-David son announced that for the first time in decades, it has begun the design of an all-new race engine. This 1000cc engine, currently in preliminary design, is not intended for dirt-track racing. Instead, Harley plans to use it to compete in Superbike roadracing. Representing a complete break from Harley traditions, this new V-Twin will use double overhead camshafts, four or five valves per cylinder, liquid cooling, fuel injection, and a V-angle wider than 45 degrees. Harley hopes to have the design work finished this spring, with engine testing beginning in late summer or early fall. The intent is to race the engine, in next year's Daytona .200. Mark Tuttle, head of Harley engineering, says the only problem he's having right now is getting his staff "to work on anything other than the new engine." Such a 1000cc V-Twin, built to the current limits of engine technology, should readily produce 140 horse power or more. Of course, one interesting result of Superbike homologation requirements is that 50 street legal motorcycles using the new engine will have to be built before it can be raced. One of these first 50 bikes might well make the ultimate Harley Café Racer, or be a near-priceless collector's Harley.
Pirelli Tour-Am
J^irelli has just joined Dunlop, Continental, Metzeler, Michelin and others in a hot part of the tire business: long-life tires specifically for Gold Wings and their like. But unlike its bias-belted competitors, the Pirelli TourAm tire uses an unbelted, pure bias-ply construction. By molding the tire to a taller shape than it assumes once mounted, Pirelli has ensured that the tread rubber runs with an initial compressive preload. According to Pirelli, this minimizes tire growth and tread squirm, allowing competitively long life without the need for belts. Supposedly, the advantage of this concept is better handling and more-even tread wear over the life of the tire.
Now that all the major tire companies offer touring tires that should last well over 10,000 miles, we predict that the competition in the touring-tire business may take some new directions, with more emphasis on wetweather traction, load capacity, handling and stability, and perhaps most important, ride quality.
And Aprilia's V-Twin
A prilia, the rising star of Italy’s motorcycle industry, is widely rumored to be working on its own 750cc fourstroke V-Twin. The engine is said to have a 90-degree Vangle, just like a Ducati or a Honda VT250, and use dual overhead cams and four valves per cylinder. While the design of this engine allegedly is an in-house project, the engine would be manufactured for Aprilia by Rotax, the Austrian company that already provides powerplants for all Aprilias of 125cc and larger.
This new V-Twin would most likely be used in a streetbike that might resemble the Ducati Paso or Bimota DB1. The announcement of such a machine might soon be followed by Aprilia’s entry into the U.S. market, an move that has awaited models more suitable for the U.S. than Aprilia’s current 125cc and Rotax-powered fourstroke dual-purpose machines.
The last Bonneville
The last Triumph Bonneville ever to be built was completed at Les Harris’s factory in England at the beginning of March; no more will be constructed now that Harris’s license from the owner of the Triumph name, millionaire businessman John Bloor, has expired. Harris built over 1500 new Bonnevilles since the closure of Triumph’s original Meriden factory, and is now concentrating on the Rotax-powered Matchless Single launched last year. It’s reported to be selling well, and in Harris’s own words, “is a much better bike.” A café-racer version, carrying the classic Matchless G50 name, will be announced later this year. Harris also revealed that he’s working on an all-new parallel-Twin that he plans to put into production in the 1990s. No further details are available at present, but it’s thought the new power unit would be built in both 400 and 750cc versions, and would be liquid-cooled with a single overhead camshaft.
Kawasaki builds a MULE
In the face of reduced motorcycle and ATV sales, one response by companies such as Kawasaki probably will be the use of existing technology to explore totally new markets. Unfortunately, the first move in this direction is less exciting to motorcyclists than might be hoped: Kawasaki’s MULE 1000. The MULE is a two-seat, offroad utility vehicle designed to fill a niche between the more work-oriented AT Vs and a mini-pickup truck. The 1000 in its name doesn’t stand for displacement, but instead for its 1000-pound load capacity.
Although it’s considerably less than a Ninja 1000 powerplant, the MULE’s engine is not totally agricultural: It’s a detuned version of the dohc Kawasaki 454 LTD engine, fitted with a Salsbury-type automatic transmission. More important design criteria for the MULE were its nearly 4-by-8-feet dimensions, just the right size to fit within the bed of a standard pickup truck.
Perhaps the only logical motorcycling use for a MULE would be as the racer’s ultimate pit runabout; but somehow, we think most MULEs will lead a far less glamorous life on the farm.
