| MODEL | HARLEY-DAVIDSON XR 750 FLAT TRACKER 1972 |
| Year | 1972 |
| Engine Type | Four-stroke, V-twin, OHV pushrod, 2 valves per cylinder, alloy heads and barrels |
| Displacement / Capacity | 748 cc / 45.6 cu in |
| Bore X Stroke | 79 x 76 mm |
| Compression Ratio | — |
| Cooling System | Air cooled |
| Max Power | Approx. 59 kW / 79 hp (estimated) |
| Max Torque | — |
| Ignition | — |
| Induction | 2 x 36 mm Mikuni carburettors |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4-speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Steel twin-loop full cradle |
| Front Suspension | Ceriani telescopic fork |
| Rear Suspension | Dual Girling shocks |
| Front Brakes | None |
| Rear Brakes | Optional |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 790 mm / 31 in |
| Wheelbase | 1441 mm / 56.75 in |
| Ground Clearance | — |
| Dry Weight | 134 kg / 295 lbs (claimed) |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 4.00 x 19 |
| Rear Tyre | 4.00 x 19 |
| FUEL SYSTEM | |
| Fuel Capacity | 9.5 Litres / 2.5 US gal |
| Fuel Consumption | — |
| Top Speed | 185 km/h / 115 mph |
Photo: Mike Schinkel, CC BY 2.0, via Wikimedia Commons
Photo: Dennis Bratland, CC BY-SA 4.0, via Wikimedia Commons
Harley built the XR-750 to race in AMA dirt track after the 1969 rule change ended the side-valve KR's advantage. The original iron-head engine overheated badly, so for 1972 the factory fitted all-aluminium heads and barrels with a bigger bore and shorter stroke, and that version is the one this page covers. It became the most successful racer in AMA history, winning titles with riders such as Mark Brelsford and Jay Springsteen, and it was also Evel Knievel's jump bike.
