Sunday Salon: Harley 750, King of the Track – Part 1

If you follow racing of any kind you know that there is plenty of variety.  If you have followed motorcycle racing you know that there is intense competition between the brands and that one brand will win for a while then another.

There is a form of motorcycle racing that is as old as motorcycles in America.  At first motorcycles were used to tow bicycles up to speed on board tracks. As motorcycle speeds increased the bicycles were forgotten.  The next step, board track racing of motorcycles was absolute carnage.  Because of the carnage, circle track or dirt track racing was developed.  This was generally on horse racing tracks and frequently used as an attraction at county fairs.  Wide open throttles with triple digit speeds, no front brakes and steering by sliding the rear wheel.  This is sane?  Compared to board track racing – absolutely yes.

One brand has been dominant through most of the history of this sport.  At times, it has required favorable rules from the American Motorcyclist Association to retain that dominance.  Today, however, with rules favoring other brands and models, Harley Davidson still dominates the flat track.  I have found the history interesting and hope you do as well.

The stereotypical Harley rider has become a middle aged professional – typically a lawyer or accountant – wearing expensive leathers and making annual excursions to Sturgis.

That has not long been the case.  Marlon Brando (seen above riding a Triumph), Lee Marvin and others established the “bad boy” image in the 1953 film classic “The Wild One”.  Stereotypes existed long before that and were based on real performance in racing – and in war.

In 1929 Harley introduced a 45 CID flathead.  Technology was standard for the era but the timing was good.

If it hadn’t been for that basic design Harley might have been just a name like Excelsior and others that never made it through the Great Depression.  Harley was facing bankruptcy and sold the license to build that model to the Japanese.  The company became known as Dabittoson Harley or Rikuo.  This model was first made by the Japanese as a 1200 and then a 750. Primary customers were the Japanese army and Japanese Police Forces.  Sources indicate that by the time the war ended over 18,000 had been made, used primarily in the Japanese war effort.

The flathead from 1929 was also the genesis of Harley Davidson’s flat track efforts.

In 1945 Harley introduced the Flathead WR.  This became one of the most winning bikes ever made. The modern flat track bike is distinctly evolved from this bike.  It still had period technology with floor shifts and separate engine and transmission but it was certainly a step towards perfecting the Buggy Whip.

A departure from the past was introduced in 1952.  It was still a flathead, but new technology took a step towards modern motorcycle design.  This bike had four short cams (one for each valve), a four speed transmission, a foot shifter, rear swingarm versus a rigid tail, telescopic forks, and a unified transmission and engine.  These modifications were necessary to keep up with the competition, especially the British.  Curiously, although this bike has a swingarm, every racing KR that I can find still shows a rigid frame.

In 1953 Harley introduced the KR 750 based on this model. It was designed just for the dirt track. Differences between the street model above and the “racing only” model below are obvious. The American Motorcyclist Association in turn reestablished rules for maximum displacement based on head and valve design.  Flatheads were allowed 750 cc while OHV designs were allowed 500.

You might think that to be a bit unfair but I have some doubts.  The British manufacturers were able to wring a lot of performance out of 500cc.  There is no comparison when it came to airflow and certainly OHV designs allow for much higher compression ratios.  The rules were the same for everyone so BSA or anyone else could have developed  a 750 flathead if they wanted to. While flatheads were at an advanced stage of development with Harley, the other design changes were absolutely necessary to stay ahead of the British. The results Harley had with the XR750 model that followed this version absolutely showed they could have departed from the flathead.  Perhaps I’m being a homer.

The public was buying 650s and they liked seeing their bikes on the track.  There was considerable pressure from the public and the manufacturers to level the playing field.  It took until 1969 for that pressure to have an effect.  In the meantime Harley won every year but 1963, when Dick Mann won for BSA, and 1967-1968 when a young upstart named Gary Nixon won for Triumph.  In 1969, Mert Lawwill won on a Harley Flathead for the last time.

If you think you recognize Mert you probably do.  If you have ever seen the film “On any Sunday” you’ve seen his story.  Here is a picture of him with a couple of friends.

From WR to KR to XR, from flatheads with separate transmissions to unit built OHV engines.  The design below is 40 years old and still winning.  To get a glimpse of the dominance this link has much more information:

The remarkable thing about this is that the rules now allow bikes up to one liter to compete.  Perhaps you can think of a bike that is more deserving of the title “most dominant bike in history” but I cannot.  At least not for a time span like this.  I feel an article coming on that is devoted to the XR and some thumbnails devoted to the men that won on them. Stay tuned.

Hope you enjoyed the ride.