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100 MPG Diesel Motorcycle - Diesel Alternatives

Combat-Tested Diesel Motorcycles Get Ready For The Asphalt Jungle

Photography by , HDT USA

You know the type. The Birkenstock-wearing, beard-stroking college professor neighbor that self-righteously drives around town in his Prius adorned with the obnoxious "Carpool Lane OK" bumper sticker. He crows ad nauseum about his vehicle's 50-plus mpg fuel efficiency and environmental friendliness. Personally, you wouldn't be caught dead in one of those nerd-mobiles. Well, imagine owning transportation with about a thousand times more character, that's infinitely more fun to drive (or ride, in this case), and gets more than double the gas mileage of that Japanese techno-marvel. And just to get the prof's politically-correct goat, it comes in two versions, one with an airbrushed American flag, the other in mil-spec olive-drab green paint.

This vehicle is not some pie-in-the-sky concept, but the real deal. It's the new diesel motorcycle offered by Hayes Diversified Technologies (HDT). But, this isn't just some slapped-together garage-built novelty for diesel nuts. This is a comprehensively engineered motorcycle, designed to withstand the rigors of combat, and will be offered to the general public in less than a year.

Fred Hayes, owner of HDT USA, gave us the background of the project and how the bike was born out of necessity. "In the early '80s, we were awarded the first military motorcycle contract since basically World War II. In 1984, NATO came out with a doctrine that all battlefield equipment had to run on one fuel. One of the only types of equipment that wasn't available as a diesel at the time was motorcycles. Following the NATO announcement, in 1997, the U.S. Navy announced that by 2005, it would not transport gasoline of any type, and would only support and supply heavy fuels, such as jet fuel, kerosene, and diesel," Hayes said.

Faced with these upcoming requirements, the Marine Corps approached multiple motorcycle manufacturers to fulfill the contract, but few showed any interest, saying that diesel motorcycles were "economically impractical" or their performance would be compromised by excess weight or lack of power. Finally, the Corps issued a final call offering financial assistance to contractors willing to produce a prototype. HDT was one of the few companies willing to take up the challenge and was awarded with the Phase II and, finally, Phase III contract to build the motorcycles.

For the time being, HDT is remanufacturing mil-spec Kawasaki KLR 650s and outfitting them with the new engine and revised suspension, since Kawasaki doesn't sell rolling chassis without engines. HDT continues to remanufacture and upgrade gasoline-powered military bikes as well, but with the new fuel requirements, is remanufacturing many of them with the diesel engine.

Several different prototype engines were built and tested using modified gasoline components, but it was ultimately determined that to meet the necessary durability and performance demands, a clean-sheet engine design was necessary.

British engineer Dr. Stuart McGuigan took the lead in developing the new diesel motorcycle engine, one uniquely suited for its mission. The result is a lightweight, liquid-cooled 611cc four-valve DOHC unit, developing 30 hp at 5,700 rpm. While this may not sound like a rousing output, it is more than double that of an equivalent-size industrial diesel engine, with approximately double the rpm range. Hayes said that in testing, the engine freely revved up to an astounding 8,000 rpm and is easily capable of more than 7,000 rpm, shattering the myth that diesel engines are incapable of speeds above 5,500 rpm. And the fuel efficiency is simply unmatched by gasoline-powered equivalents. Bikes equipped with this engine have achieved 96 mpg in military-certified testing, and in a street tune should be capable of 102 mpg, according to Hayes. He said the engine responds well to a variety of heavy fuels, including kerosene, JP8 (the standard fuel of the U.S. military), and biodiesel. Although the engine runs a little smoky on JP8, Hayes says on EPA pump diesel, the smoke is nearly non-existent. Not resting on his laurels, Hayes is already anticipating and preparing for the '08 diesel motorcycle emissions standards and is confident the bike will meet or exceed them.

The engine's penchant for revs belies its compression-combustion design. Other than a somewhat noisy idle, at speed, the engine sounds similar to any other large-displacement single. And although it's no match for a Suzuki Hayabusa or other crotch rockets, it's capable of 90-plus mph, making it more than freeway capable.

You may be thinking, "Why don't they throw a turbo on that thing?" a question that Hayes himself asked. However, for its intended mission, a naturally-aspirated engine was the best fit. "In terms of throttle response, simplicity, and ease of maintenance, we determined a naturally aspirated engine was the way to go. We've tested some turbocharged prototypes, but the complexity, packaging, and heat-dissipation issues that come with a turbo ruled that out for the military bikes. However, down the road, we're looking at a possible V-twin diesel with a turbo option, but that's several years away," Hayes also said that the unique design of the HDT engine gives it a dynamic operating range far higher than most conventional diesels, allowing it to produce peak power where most conventional, even turbocharged diesels fear to tread.

Hayes has not yet announced pricing for the civilian model, but said that consumer interest and inquiries have been "overwhelming" so far. It's expected that the price tag of the consumer-ready version will likely carry a 20-to-30-percent premium over an equivalent gasoline-powered motorcycle. Hayes expects to start offering street-legal versions of the bike around April of 2006.

Diesel
M1030M1 JP8/Diesel Military Motorcycle
Engine:
Type: Four-stroke, indirect-injection, single-cylinder, liquid-cooled
Displacement: 611 cc
Power: 30 hp at 5,700 rpm
Torque: 33 lb-ft at 4,200 rpm
Lubrication: Wet sump, compatible with MIL-L-2104 lubricant
Air Filtration: High-capacity, three-stage, oiled foam, reusable
Transmission: Five-speed, constant mesh, return shift
Final Drive: Self-lubricated, sealed, O-ring roller chain

Weights & measurements:
Dry Weight: 369 lb
Max. Width: 35.75 in
Max. Length: 85 in
Wheelbase: 57 in
Ground Clearance: 10.7 in

Performance:Acceleration: 0-30 mph (53 kph), 3.3 sec 0-60 mph (106 kph), 9.7 secGradeability: 60% (32E)Turning Radius: Less than 7 ftMaximum Speed: In excess of 90 mphMinimum Constant Speed: Less than 3 mphWater Fording Depth: 24 inFuel Mileage: 96 mpg at 55 mph (Tested)Range: 408 miles at 55 mph

Gasoline
M1030B1 Gasoline Motorcycle
Engine:
Type: Four-stroke, single-cylinder, liquid-cooled
Displacement: 651 cc
Power: 48 hp at 6,500 rpm
Torque: 40 lb-ft at 5,500 rpm
Lubrication: Wet sump, compatible with MIL-L-2104, MIL-L-46152, and MIL-L-46167 lubricantsAir Filtration: High-capacity, three-stage, oiled foam, reusable
Transmission: Five-speed, constant mesh, return shift
Final Drive: Self-lubricated, sealed, O-ring roller chain

Weights & measurements:
Dry Weight: 358 lb
Max. Width: 35.75 in
Max. Length: 85 in
Wheelbase:
57 in
Ground Clearance: 10.7 in

Performance:
Acceleration: [0-30 mph (53 kph)]: 2.4 sec, [0-60 mph (106 kph)]: 5.7 sec
Gradeability: 60% (32E)
Turning Radius: Less than 7 ft
Maximum Speed: In excess of 105 mph
Minimum Constant Speed: Less than 3 mph
Water Fording Depth: 24 in
Fuel Mileage: 55 mpg at 55 mph
Range: 335 miles at 55 mph

SOURCES
Hayes Diversified Technologies
www.dieselmotorcycles.com
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