Harley 750, King of the Track, Part 1

Another fine 2-wheeled post by Lee Wilcox! Enjoy. -Klockau

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:  http://www.motorsportsetc.com/champs/ama_gn.htm

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.

10 Replies to “Harley 750, King of the Track, Part 1”

  1. Avatar-Nate

    Thank you .

    I rode Harley’s in my youth and have many fond memories of my ’65 FL PanHead ex L.A.P.D. and my ’37 EL KnuckleHead I rode all over Guatemala in the mid 1970’s .

    A stock K model is a dream bike for me, not very fast but a fun bike to ride for sure .

    -Nate

    Reply
  2. AvatarJohn C.

    Thanks Lee and Tom for telling us this story. It is fun to think of American Harleys refining slowly proven technology to stay ahead of the British with their more advanced but perhaps more problematic technology. Also nice the locals slightly tilted the table toward the home team. I am sure the British did the same at home.

    Nice to see the mention of the Japanese Harley connection. With our Japanese friends, well they weren’t our friends yet, putting aside all the cycling ideas no doubt spewing forth from their technology centers to build the simple Harley under license, what a complement!

    Reply
  3. AvatarDirty Dingus McGee

    The one bike that scared the AMA and Harley so bad that it was banned after it’s first race

    Reply
    • AvatarAlan K

      You gotta just love the way KR barrels into that first corner – no holds barred 🙂

      The AMA were probably right to bar the TZ in terms of keeping the racing competitive and low(ish) budget – if that was the objective – but in truth it is/was a pretty sad indictment of the archaic engineering in the Harleys of the day.

      Reply
      • AvatarDirty Dingus McGee

        While I enjoy watching multi cylinder bikes race, I will confess to only owning 2 in my lifetime; in 1974 I bought a 72 Honda 750(sold in early 76), and in 2004 a 1985 BMW K100RT (still have it). Except for a handful of “one lungers” all the other, probably 35 different bikes, have had 2 cylinders. Some vertical, some V, some boxer, but twins. I like the sound, the power delivery and not having to dance on the shifter like its a snake I’m trying to stomp to death.

        Reply
        • Avatar-Nate

          Agreed ~

          If you like to ride, twins are the very best, vertical, boxer, slopers, V twins ~ they’re all nice .

          If balls to the walls speed is your need, multies are perhaps the way to go .

          Like with many cars/trucks, driving a slow rig fast can be ever so much more fun, it puts the onus on the operator, not just having blind power all the time .

          -Nate

          Reply
  4. AvatarDirt Roads

    I can’t count how many times I’ve watched “On Any Sunday” – it’s an all-time classic.

    That said, I’ve never cared for Harleys, and have ridden choppers, Harleys with side cars and others – just never cared for them. Not my style for riding. And my old Sabre 65 passed them all on the highway, whether they were running or not. But it’s like Jeep I guess – it’s a “Harley thing” and if you don’t get it, you don’t get it. I’m just not a straight line rider, more of a dirt biker and road racer.

    My wife, on the other hand, prefers bikes that go thump over bikes that, as she says, sound more like a sewing machine. Go figure.

    Thanks for the write-up, TK.

    Reply
    • Avatar-Nate

      You explained it very well .

      I rode Harleys and had fun but I like and prefer, the twisty bits, one time I was riding my PanHead full tilt boogie on the Angeles Crest Highway, dragging the frame as always when a kid on a single carby Triumph passed me like I was parked, the blush flew off the Harley Davisdon rose that moment, no regrets either way .

      -Nate

      Reply
    • Tom KlockauTom Klockau Post author

      Thanks, but I didn’t write it, Lee did. There are several more motorcycle articles of his that I’ll be re-publishing here soon, so stay tuned.

      Reply
  5. Avatarrambo furum

    If asked, I’d have said that H-D cowered away from advancement and competitiveness and decided to remain stuck in the past around the time of the moon landing, a half century ago, so I’d be correct.
    It’s worth noting that the Hells Angels rode Harleys because they were, were, the fast bikes of the time.

    Reply

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