Break It Down
As you might already know, the XR's air-cooled, silver powdercoated 1203cc Evolution mill is nearly standard issue Sportster equipment, but with notable upgrades under the hood. The major bits include a larger, more efficient airbox, performance cams, downdraft fuel injection and new oil-cooled heads. An upswept, high-volume 2 into 1 into 2 exhaust system is likewise optimized for efficiency. Toss in a higher 10.0:1 compression ratio and an increased redline of 7000 rpm, and the result is a claimed torque figure just shy of 74 lbs-ft at a low 4000 rpm, with an alleged 90 horsepower at 7000 rpm (more horsepower but less torque than you'd find in other 1200 Sportsters).