The oldest and most traditional type of racing sanctioned by the AMA is flat track—sometimes referred to as dirt track”—racing. Dating back to post-World War II, flat track is the uniquely American type of motorcycle racing. Racers maneuver their machines through turns, inches from each other, at speeds over 100 mph.
Prior to 1954, the focal point of flat track racing was the Springfield Mile at the Illinois State Fairgrounds. The 25-mile race was the most prestigious event that determined the winner of the AMA National Dirt Track Championship. In 1954, the AMA established the Grand National Championship series.
Initially flat track and road racing were in the same discipline, but in 1986 the AMA decided to separate the two. In the last 10 years there has been a great push to heighten the visibility of the sport. The AMA has worked hard to acquire broadcast contracts and sponsorship. They set new equipment guidelines to bring more manufacturers and teams into dirt track racing at the Grand National level.
During 1999-2001 seasons they began testing the 1000cc engine formula rather than the traditional 750cc engines previously used. Although the SuperTracker series was discontinued in 2001, the research led to valuable insight.
Today, AMA flat track racing is divided into two distinct classes: the AMA Grand National Twins Championship held on the mile and ½ mile and the AMA Grand National Singles Championships held on the short track. These classes travel under the banner of the AMA Flat Track Championship.
Prior to 1954, the focal point of flat track racing was the Springfield Mile at the Illinois State Fairgrounds. The 25-mile race was the most prestigious event that determined the winner of the AMA National Dirt Track Championship. In 1954, the AMA established the Grand National Championship series.
Initially flat track and road racing were in the same discipline, but in 1986 the AMA decided to separate the two. In the last 10 years there has been a great push to heighten the visibility of the sport. The AMA has worked hard to acquire broadcast contracts and sponsorship. They set new equipment guidelines to bring more manufacturers and teams into dirt track racing at the Grand National level.
During 1999-2001 seasons they began testing the 1000cc engine formula rather than the traditional 750cc engines previously used. Although the SuperTracker series was discontinued in 2001, the research led to valuable insight.
Today, AMA flat track racing is divided into two distinct classes: the AMA Grand National Twins Championship held on the mile and ½ mile and the AMA Grand National Singles Championships held on the short track. These classes travel under the banner of the AMA Flat Track Championship.
XR750
In 1970 the XR-750, a Sportster based motorcycle was created by Harley-Davidson for Class C racing, according to AMA rules of the time. The 1970 Iron XR was the first year of production. There were close to 200 of these “Iron” XR’s made to meet the AMA’s racing criteria. The HD race department found out shortly after a few races that the frames needed modifying. The steel top end of the motor was heavy, extremely hot and locking up due to the heat. When HD realized the Iron XR just wasn’t competition worthy, they disassembled and destroyed about 80% of them. They cut the frames in half and thru them in the dumpster. When the Iron XR was abandoned a lot of the guys turned them into street bikes because it was almost a Sportster motor.
In 1972 a new, aluminum alloy XR-750 is introduced. It is more powerful and more reliable than the earlier 1970 “Iron” model. There were a total of 520 XR-750’s produced approximately 200 in the second year.
A service bulletin came out from the factory early in 1972 that the XR needed oil for the flywheels. Most motors were then cut for a sump body.
XR-750’s were like a rocket ship without brakes, 100 HP, 295 lbs., sleek and stylish.
Every XR is rare, but a stock XR is the rarest. The last production year was 1980. In between this they made 1974/75 and 1977’s. They only made a total of 76 bikes in 1977.
The 1980 is a refined sleek looking, XR. The reason HD stopped producing a complete bike in 1980 is because the racers would pull the motor, roll the chassis into a corner or throw it away, and then put the motor into a complete aftermarket racing chassis. In 1980 to 1988 Harley only sold the motor. By 1985 most of the other XR parts were considered obsolete and no longer available.
In 1988 Harley stopped assembling the motors for sale because the racers would tear the completed motors apart and rebuild it their way. Then they stopped porting the heads because no one wanted Harley’s porting. The motor was just sold in kit form as parts from that point on.
Most of the XR-750’s are in museums, collections or are being vintage raced. A good many of the XR’s ended up in junk piles by the hill-climbers. Racers of all types from 1972 to present have and still value the XR motor for racing.
The motor virtually unchanged with the exception of porting, bearings and a standard 40 over bore, is still being raced at the time of this letter. Externally viewed it is the same as it was in 1972 and a new motor will still bolt to a 1970 frame.
By the mid-1970s, Harley-Davidson was the leader in the AMA Grand National Series. The XR750 based racer would go on to become the commanding dirt track motorcycle in the history of the series. Mark Brelsford won the Grand National Championship in 1972 on the XR-750. Scott Parker won the Grand National Championship on an XR-750 nine times. Evel Knievel used a 1972 XR-750 motor in a 1970 chassis for his famous jumps.
In 1970, Evel Knievel began using the XR-750 for his daredevil jumps. Although built to race, Knievel used the motorcycle and the Harley-Davidson sponsorship until 1977. The longest jump made by Knievel on the XR-750 was 133 ft (41 m) at Kings Island in 1975. In the 1980s, motorcycle jumping changed using motocross motorcycles, which were built to jump. However, daredevil Bubba Blackwell currently uses the XR-750 for jumping. Blackwell holds all jumping records on the XR-750, jumping 157 ft (48 m).
One of Knievel's signature red, white, and blue XR-750 motorcycles is currently housed at the Smithsonian American History Museum.
XR-750TT
There were 10 original factory XRTT’s made. They were raced for several years and then interest went away on them. At that time, they were just a road race bike that the factory put out. These were not really considered a production racer. The 10 factory riders used them just as they would any other race bike. The H-D race department would build and tune their bikes.
There were quite a few other XRTT frames that became available to privateers. These came in the form of a kit; frame, wheels, forks, glass, everything but the motor.
Back in the 1970’s racers would compete on a TT course, dirt track course and a road race course. Riders that wanted a lot of points would compete on the road race circuit when they weren’t dirt tracking. This meant they had to take the TT rolling chassis along with their dirt track bikes. They would pull the dirt track motor, refine the gearing and put the motor in the road race chassis. Few were lucky enough to have a spare motor to put in their TT chassis.
Over the years these XRTT’s were just parked around the country and never given much consideration. When vintage racing began and collectors realized that the XRTT was an extremely rare bike, everyone wanted one.
The original factory race bikes were raced, modified, disassembled and the parts were scattered throughout the country.
XR1000
Harley's XR-750 racing bike enjoyed such success on the nation's flat tracks that a street version was introduced in 1983 to capitalize on the notoriety.
Though based on the stripped-down XLX Sportster, the XR-1000 was fitted with special cylinder heads similar to those found on the racing version.
These had intake ports entering the rear of both cylinders fed by dual carburetors on the right-hand side, and front-exiting exhaust ports emptying into high-mounted dual mufflers that exited on the left.
By contrast, all other Sportsters had a single carb (also on the right) that fed to centrally mounted intake ports, with exhaust exiting on the right from outboard ports.
The modifications resulted in an output of nearly 70 horsepower, a figure only dreamed of for other Sportsters, and gave the XR-1000 acceleration unequaled by any other street motorcycle Harley had ever built.
Unfortunately, the race-bred hardware that made the XR-1000 quite fast also made it quite expensive. At nearly $2,000 more than the XLX, not enough riders appreciated the difference, and the XR would fade into the sunset after the 1984 model run.
XR1200
In the 2008 model year, Harley-Davidson released the XR1200 Sportster in Europe, Africa, and the Middle East. The XR1200 had an Evolution engine tuned to produce 91 bhp (68 kW), four-piston dual front disc brakes, and an aluminum swing arm. Motorcyclist featured the XR1200 on the cover of its July 2008 issue, and was generally positive about it in their "First Ride" story, in which Harley-Davidson was repeatedly asked to sell it in the United States. One possible reason for the delayed availability in the United States was the fact that Harley-Davidson had to obtain the "XR1200" naming rights from Storz Performance, a Harley customizing shop in Ventura, Calif. The XR1200 was released in the United States in 2009, in a special color scheme including Mirage Orange highlighting its dirt-tracker heritage. The first 750 XR1200 models in 2009 were pre-ordered and came with a number 1 tag for the front of the bike, autographed by Kenny Coolbeth and Scott Parker and a thank you/welcome letter from Harley-Davidson, signed by Bill Davidson.
