1952 - 1970 Harley Davidson KRTT 750
WR, KR, XR. Since 1941, Harley Davidson
Motor Corporation has provided racers with purpose built race machines. The WR
had a tank shift with a foot clutch and separate engine and transmission. The
1952 KR was of unit construction with a foot operated shift and hand clutch.
Both of these models were side valve flatheads. The mid 1970 XR was of overhead
valve design and continues through today. The Harley Davidson Dr and DRTT ruled
dirt track and road racing in the United States for decades, winning almost
every worth winning from Dodge City, Kansas, to the Daytona 200. And the KRs
continued to be victorious even aft its production life had ended in 1969. The
cycle moved on to a second life, out of production, as the machine of choice
for many dedicated competitors.
The Famous - and Infamous -
The V-twin engine that powered the KR and KRTT was a sidevalve engine
that started life at 744ccbut usually needed to be re-bored after break-in; the
AMA race ruling body allowed the KRs to run a 0.045in overbore bringing the
engine to a full 767cc. with a Fairbanks-Morse farm tractor style magneto
providing spark the famous V-twin delivered 48hp.
Iron Men and Iron
No one ever merely flicked a KR or DRTT into a turn the iron engine
machines responded only to iron willed riders. They were large heavy and
powerful, and piloting them was a chore. Top speed on the Daytona banking with
full fairing was clocked at 150mph, but eventually by the mid sixties the
nimble, lightweight British twins outran the KRs and KRTTs on their home
ground, signaling a new era of foreign motorcycle dominance in the United
Man and Machine
The list of men associated with the WR/KR/XR
models is a who's who of American racing. Names like Sifton, Arena, Huber,
Lawill, Andres, Leonard, Resweber, Markel, Roeder, Reiman, Peel, Brelsford,
Scott, Springsteen, Tilley, Carr, Parker, O'brien, and many others. Some of
these men built careers upon dthe special knowledge that made Harleys fast,
designing modified parts for the privateer.