As you can guess this thread is a compare and contrast of my two motorcycles . Both Air/Oil cooled , OHV Hydraulic roller Lifters , 2 Valves per cylinder , Dry Sump Oil System capacity : Norton 2.3 L , HD 3 US Quarts with larger oil filter. Transmission and Primary share same Oil : Norton 1.2 L , HD 1 Quart Similar Power delivery and levels : Norton 69 RWHP measured , HD 79 RWHP Cycle World Magazine. (HD has more low end torque) RPM at 70 MPH (Top 5th gear) : Norton 4200 rpm , HD 3500 rpm (Japan Gearing). Speedometer Error at 70 mph : Norton 66.5 mph actual , HD 70 mph actual . Rev Limiter cut in : Norton 7800 RPM , HD 6850 RPM . Wet weight : Norton 515 lbs , HD 579 lbs Both bikes transmit some vibration to the rider , The HD has slightly less felt at 70 MPH , but more than Norton at lower revs and especially Idle . Fuel Economy same loop 70 miles same indicated speeds and driving style throughout : Norton 51.7 MPG , HD 50.2 MPG Comfort seating and bars : Currently HD has the edge with a larger seat and higher bars. BUT ! I like them both and can ride them both for a long distance (tested) .