The 1969 Harley-Davidson XR750 Werner “Prototype” Flat Track Racer

Illustration and words by Martin Squires

At the end of 2014, I visited the NEC in Birmingham in the UK to sketch at a motor show. Looking around the Harley-Davidson Riders Club booth, I spotted this muscular Harley-Davidson XR750 that just looked the part. I sat down and drew it without looking at the information boards. I was approached by its owner Alastair who informed me that it was a piece of flat track history.

Bought as a road-legal machine in 1992, Alastair didn’t know much about flat-track racing back when he hadn’t even seen the movie On Any Sunday. When a listing for the XR750 appeared, Alastair went to have a look, more out of curiosity than with the intent of buying the machine. Once he had seen and heard the real thing, it was a different story; he had to have it.

After retrieving the machine, Alastair quickly checked the engine number: 69XR001 and based his research on that linchpin. Writing to Allan Girdler, well-known Harley-Davidson expert Alastair hoped to find out more. Allan immediately knew what the engine was and responded by asking “You don’t know what you got.”

From there a great story unfolded.

Features

  • Engine: Harley-Davidson ‘Iron’ XR750, air-cooled, 4-valve, 45-degree V-twin
  • Carburetor: Mikuni 38mm.
  • Gearbox: 4-speed close ratio.
  • Ignition: Fairbanks-Morse double fire magneto.
  • Frame: Werner chromoly duplex with rectangular section swingarm.
  • Suspension: Ceriani 35mm fork and Koni Special D twin shocks.
  • Lester: 312 pounds

In 1968, the AMA (the governing body of motorcycle racing in the United States) decided to abolish the OHV (overhead valve) equivalency rule for the 1969 dirt season and 1970 for road racers . The rule had allowed 750cc side-valve machines like Harley’s KR to compete with 500cc overhead-valve machines.

Harley-Davidson had previously worked on an OHV replacement for the KR but lacked the funds to develop it properly. They began work on an interim solution but were unable to enter them in the national championship until 1970 as they were unable to produce enough OHV machines to comply with the homologation rules which required 200 motorcycles.

At the same time, Bill Werner was working in the HD racing department as an engineer. Outside of working hours, Bill started working on his own OHV racing project, doing similar things but in his own way. Starting with parts from the Harley XLR and XL road bike, modifying the pistons and making their own cams and working on the valves and head, which included locating the plug in the middle of the head for a better combustion.

Breathers, vents and drains were added to draw air into the crank case which in turn pushed through the oil which helped cool the usually hot Sportster engine which had heads and cast iron barrels. The reduction in compression also helped keep the engine running at a more reasonable temperature.

Bill was the first to make these changes and he made them with great precision. Alastair said the first time he heard the machine start up, it was running like a clock, which he hadn’t expected from such a muscular machine. It wasn’t long before HD started posting in their racing department bulletins that engineers should follow suit and reduce compression and improve crankcase ventilation and oil cooling.

Front Art Harley-Davidson XR750

Bill didn’t just work on the engine, he built the chassis himself in his basement at home, helped by his brother. With Alastair’s initial purchase, he lacked the stock frame, as with most race bikes, parts had been removed and moved around when the bike changed incarnations.

One day, out of the blue, he got a call from historic flat track racer George Wills who had bought a bunch of spare parts from Bill Werner, including the stock frame. George offered that they swap frames as he was restoring an original XR and wanted to see Werner’s original frame that he had put together with Alastair’s engine.

Alastair traveled to the United States and the deal was done. While in the United States, Alastair met Allan Girdler and Bill Werner and, thanks to this unique opportunity, discovered more about the history of the machine.

Harley-Davidson XR750 Artistic Action

In 1970 the machine was raced independently of the HD racing team by No. 73 Sid Carlson. Sid, a close friend of Bill Werner, was one of the best riders of the time, getting good positions in national races and making money competing in county races where he excelled on the XR. During this time, Bill was able to use the bike as a test bed and test his ideas.

The knowledge gained from racing the prototype independently was passed on by Bill to the engineers in the HD Racing department. Bills’ efforts and later knowledge of what could be done with the aerial XR750 led to the HD production of the 1972 XR750, which, with alloy heads and barrels, became the most successful racing motorcycle ever. in the world. Evolutions of this machine still a winner on clay ovals today. Production finally ceased in 2015.

In due course, Bill Werner installed an alloy XR motor on his frame, installed the iron motor in a stock XR frame, and then sold it. It continued to be raced in this form until 1974 when brakes were added to make it road legal. It was used in Canada until 1984 when it was sold to a buyer in the UK, passing through a few owners until Alastair purchased it.

After purchasing the machine and subsequently discovering this significant turning point in dirt track history, Alastair spent the next 20 years faithfully and sympathetically restoring this prototype machine to the condition in which it was used. . For my part, I’m glad he did because, with his battle scars, he’s a real special bike.

Special thanks to Alastair McQuaid for his help and time with this article

Harley-Davidson XR750 Art Port

Harley-Davidson XR750 Art Port

Wiley C. Thompson