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Posts Tagged ‘liquid-cooled’

1970 Harley-Davidson XR-750

I’m talking about the Harley-Davidson XR-750, which last month marked the 50th Anniversary since it’s debut.

From 1953 to 1969,  Harley-Davidson manufactured the KR750, the backbone of American dirt track racing.

The motorcycle engine was an air cooled, side valve 4-stroke 45° V-twin (flathead), 45.125 cu in (739.47 cc) displacement built for racing.  Unique for Harley’s at that time, the KR model shifted on the right, like a British bike, which worked great for dirt track.  It wasn’t until 1975, when DOT specified that all motorcycles sold in the U.S. had to have a standardized, left-side gear shift.

Harley-Davidson Flat Track Racing

Prior to 1969, the American Motorcyclist Association (AMA) rules for the Grand National Championship were structured to favor “sidevalvers” (side-valve engines) rather than overhead-valve (OHV) engines.  The intent was to deliberately favor American made bikes such as those from Harley-Davidson with their side-valve engines, and disadvantage the competition which was mainly from British manufactures i.e., Triumph, BSA, and Norton. The AMA rules allowed side-valve engines of up to 750cc capacity but OHV engines were limited to 500cc. The 50% engine size advantage stacked the odd in the favor of the side-valve bikes.

As you might imagine, the British manufactures complained…about everything—the rules, the manufactures, the officials, the drivers, the races, and the racing itself.

Harley-Davidson XR-750

As a result, in 1969, in prep for the 1970 race season, the AMA approved that all professional Amateur & Expert dirt track and speedway engines could be 750cc, regardless of configuration or valve style. This rule change eliminated the 250cc penalty for OHV engines that had existed since 1933.  Many British manufacturers begin designing and developing OHV 750cc engines for competition. To be approved by the AMA (for Class C competition), a motorcycle must be a standard catalogued production model and at least 200 units of the same model with identical engines and transmissions and must be available for inspection and/or purchase within the United States.

XR-750 Engine – Ported and Polished Heads

Unhappy with the decision, but with a desire to continue the racing legacy, Harley-Davidson set out to create a new overhead-valve racing motorcycle.  The Milwaukee motor company leveraged their OHV V-twin racing engine based on the Sportster XLR.  However, it’s engine had a displacement of 900cc (55 cu. in.) and would need to have its capacity reduced to 750cc. Harley-Davidson engineers accomplished this by decreasing the engine’s stroke from 3.81″ to 2.983″ and increased the bore from 3.0″ to 3.2″ bringing the engine in just under the 750cc maximum.

The AMA approved the Harley-Davidson “XR”, a 750cc V-twin overhead valve engine, for Class C competition on Feburary 27, 1970. It had been tentatively approved in late-1969 as the “750 Sportster”, but the motor company lacked having 200 units available for inspection at the time. The motorcycle is dubbed the “iron XR“, or “Iron Head,” due to its steel cylinders and heads.

Even Knievel

For the 1972 race season, there were a number of changes.  A vote was taken on November 18, 1971, and the AMA Competition Congress voted to allow qualified women to compete in all forms of AMA Racing.

The Water-Cooling was approved, as long as it is an integral part of a production motorcycle.  Titanium frames were outlawed from all AMA competition. The AMA approved the Harley-Davidson XR-750, an updated version of the XR, for Class C competition on April 12, 1972. The updated engine used aluminum cylinders and heads to address the overheating issues that plagued the XR model. However, due to delays in getting all 200 units completed, it wasn’t approved in time for the Daytona 200, but debuts at the Colorado Springs national on April 30, 1972.

Speaking of aluminum heads, they were made, then shipped to Jerry Branch of Branch Flowmetrics in Long Beach, California to be ported and assembled. The new cylinder head design included larger valves. The cylinder heads were then shipped back to Harley-Davidson’s factory in Milwaukee for fitting to the new engines. This V-twin engine was not quite of the same dimensions as the Iron Head. The bore was increased to 3.1” and the stroke reduced to 3”. Carburetors were 36mm Mikuni, one for each cylinder. The exhaust systems were mounted high on the left side of the motorcycle well away from the carburetors.  Power was 82hp at 7,700rpm giving the bike a top speed of around 115mph.

Harley-Davidson Flat Track Racing Team

Branch wrote engineering books on his engine air flow work and eventually sold Branch Flowmetrics to Mikuni in the late 1990s.  Branch was the only independent company to ever supply Harley-Davidson ported and polished heads!

In 1972, Harley-Davidson was the first-ever “Grand National Manufacturer’s Championship“, which compiles the highest finish of each brand at every Grand National Championship event.  Between 1972 and 2008, the XR-750 won 28 of 37 AMA Grand National Championships. The XR-750 racked up more wins than any other motorcycle in AMA racing history and earned the description of being the “most successful race bike of all time.”  In addition, the XR-750 became a cultural icon with legendary stuntman Evel Knievel at the handlebars. Evel Knievel began jumping an XR-750 at the height of his career from 1970 to 1976.

Harley-Davidson created one of the greatest bikes in the history of American motorcycling.

For 2020, the Harley-Davidson Factory Flat Track team will use the updated Harley-Davidson® XG750R flat tracker, powered by the liquid-cooled, fuel-injected and race-tuned 750cc Harley-Davidson® Revolution X™ V-Twin designed for the Street 750 motorcycle.

Full details on the Flat Track team can be found HERE.  Flat Track racing news is HERE.

Photos courtesy of Harley-Davidson

All Rights Reserved © Northwest Harley Blog

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1984 Honda Magna (VF700C or V42)

It’s a play on George Orwell’s dystopian 1949 novel 1984 — where the world in 1984 is under control of Big Brother and the Thought Police who enforced the rules against individuality and original thinking — essentially praising society’s achievement on the “Unification of Thoughts.

Taking a page from Apple’s Super Bowl ad, my “1984 wasn’t like 1984,” — thumbing my nose at the roots of America, I purchased a little slice of freedom and original thinking in the form of a Honda VF700C or V42 Magna.

That shiny jet black Honda Magna (V42) had a liquid-cooled, double-overhead cam 90° V4 engine (displacement is 699cc or 42.7 ci) with four valves per cylinder and a compression ratio of 10.5:1.  Honda claimed it’s output was 82 crankshaft HP at 9,500 RPM.  The motorcycle had a smooth shifting 6-speed transmission, a wet multi-plate clutch that was hydraulically activated and shaft final drive with helical gearing in the rear-drive unit.  The motorcycle featured twin horns, coil rear springs, hydraulic clutch, air preload front fork with anti-dive valving, and an engine temperature gauge.

1984 Honda Magna (VF700C)Specs

Braking was delivered via a hydraulic activated double twin-piston disc brakes up front and a traditional non-ABS mechanical internal expanding drum brake in the rear. Great for leaving skid marks, but not so much for stopping!

The instrumentation was housed in chrome and included an analog speedometer, tachometer and engine coolant temperature gauge, along with lights for oil pressure, neutral, turn signals, tail light burn-out and a light that illuminated “OD” which let the rider know the transmission was in 6th gear.

As I reminisce on riding the Magna, I recall it having good power and a broad torque band.  Given its light weight and low center of gravity, the motorcycle was easy to ride in the city or a twisty two-lane country road. The Magna’s features were truly pushing the state-of-the-art for a production cruiser in its day.

From a historical viewpoint, only a few years had past since Harley-Davidson executed the epic buy back from AMF.  Their sales hadn’t reached the levels they envisioned, in part, because the AMF era was famous for shoddy quality, bikes requiring a lot of maintenance and the Milwaukee motor company was getting knocked down publicly and in need of some sunshine.

The poor quality and hi-maintenance requirements on Harley motorcycles was a key factor in my decision to purchase Honda.  In fact, a member of our posse also purchased a Honda, a V65 Magna (VF1100C) the same year.  Man, those V65 Magna’s (1,098 cc) were fast.  It was Honda’s initial entry in the “1/4 mile wars” between all the Japan manufacturers during the ’80s.

As Harley skidded toward bankruptcy, you might recall they petitioned and lobbied the Reagan administration in 1982 to raise tariffs on Japanese manufacturers because of “Dumping.”

“Dumping” in this context refers to exporting a product at a lower price than is charged in the home market, or selling at a price that is lower than the cost to produce it.  In April 1983, President Reagan signed into law an act that imposed draconian import tariffs for a five-year period on Japanese motorcycles with a displacement of greater than 700 cc.  This would give the sole American motorcycle maker some breathing room from intense competition to retool, get its act together and turn profitable.

However, Honda quickly responded to the retaliatory import duties and retooled the engines (what had been the 750cc class, VF750C V45 Magna) to displace just under 700cc; making them immune to the financial impact of the tariff.  One of the bikes that debuted as a “tariff buster” in 1984 was the V42 Magna.  Ironically and in a show of engineering superiority, it had three additional horsepower compared to the 750cc!

Harley was eventually able to turn a corner and the motor company ultimately requested that the tariff protection end early — essentially stating, they were now strong enough to take on the best competition in the world!

While the act was supposed to last for five years, then CEO Vaughn Beals asked that it be lifted a year early in 1987.  The 5-year tariff officially expired in 1988. That same year the Honda Magna reverted back to its original size of 748 cc.

Photos courtesy of Honda and Harley-Davidson Museum.

All Rights Reserved © Northwest Harley Blog

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Pan America™

At the EICMA (Esposizione Internazionale Ciclo Motociclo e Accessori), motorsports show in Milan, Italy, earlier this week — Harley-Davidson debuted two new bikes.  Important to note is the difference in the terms “launch” vs. “debuted.”

The Milwaukee MoCo has aimed one of motorcycles at a market segment in which Harley-Davidson has never really participated.

It’s my view that Harley-Davison is slowly trying to build higher walls to keep “enemies” (competitors) from invasion. Marketing types call this “relevance” and “barriers to entry.”  Multiple financial reports from the company clearly indicate a struggle to fire up a new generation of riders.  The growing presence of electric vehicles is undeniable, but the premium-priced electric (LiveWire) motorcycle — is a non·start·er in terms of revenue!

And at the same time, there’s been an invading army (BMW, KTM, Triumph, Yamaha, Honda or Ducati counterparts) of adventure touring bikes (ADV).  Importantly, this segment is where customers seem particularly excited to buy new models year-after-year.  Even Italy’s floundering boutique bike builder, Moto Guzzi, has had to double the workforce in its Mandello del Lario plant to keep up with demand for the new V85 TT adventure bike ($12,990).  It’s simple.  A fresh new design, a fresh new motor, and a capable around town, comfortable on freeways and durable enough for off-road riding gets customers excited to put down money!

We could have a long-debate on why Harley-Davidson spent millions of R&D dollars much too early as part of their electrification strategy and if the mainstream motorcycle market is ready to encourage motorcyclists to switch to electric vehicles.

But, lets return to the point at hand.

The first new motorcycle is an adventure touring bike (ADV) called the Pan America™.  Astute readers are likely to have déjà vu as it looks very similar to the Pan America concept motorcycle teased out back in 2018.

The Pan America has a new liquid-cooled 60-degree V-twin engine labeled the Revolution Max that displaces 1,250-cc and is reported to make 145 horsepower and more than 90 pound-feet of torque. Impressive stats, especially for the MoCo, which typically has built larger displacement engines with less power and more torque.  The new ADV motorcycle differs from traditional Harley models.  The first item, is exchanging the belt-style final drive for a chain drive that allows simpler gearing changes and improves on the ability to repair if something goes sideways on the trail.  The ADV also leverages a rear trellis-style subframe for strength and reduced weight, which allows motorcyclists to mount different types of adventure-isk luggage to it.

Other advancements include new radial monoblock four-piston caliper brake system developed in collaboration with Brembo and an inverted fork setup, which is common on ADV bikes.  From a styling perspective, you’ll either love the bird-beak nose and squinty cyclops-like headlight or not.

Harley-Davidson® Bronx™

The second new motorcycle is a middleweight class and called the Harley-Davidson® Bronx™. It’s reported to have a smaller 975-cc version of the Pan America’s Revolution Max engine and produces 115-horsepower and 70 lb.-ft. of torque.  Style wise, the Bronx looks somewhat cookie-cutter in this crowded “streetfighter” market segment.  From press photos the motorcycle appears to be belt-driven.  Both motorcycles will roll on new co-branded Michelin tires.

Harley-Davidson says that it’s aiming to have both the Pan America and the Bronx in showrooms by the end of 2020.

Huh?!  A year away?

I like the adventure touring bike (ADV) lineup, but if I was in the market to purchase, it’s unlikely that I’d stall buying for a year to purchase an unproven ADV motorcycle.  I also think it will be a mistake if the MoCo expects its Harley-Davidson name to garner an ultra-premium price in this new segment as it has in the EV market with the LiveWire.

The Pan American should launched and be in showrooms in March 2020, not “late” 2020.

Photos courtesy of Harley-Davidson

All Rights Reserved (C) Northwest Harley Blog

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