Regardless of how you feel about the displacement, you'll have to admit the Vulcan 900's newly minted V-twin is the business. Kawasaki's engineers took the basic architecture of the 800's air- and liquid-cooled, SOHC, eight-valve 55-degree V-twin and gave it a longer stroke (66.2mm to 74.2mm) to bring displacement to, you guessed it, 903cc. They also bolted on twin-butterfly fuel injection with 34mm throttle bodies, and a fast-idle system like that on Kawasaki's maximum Vulcan, the 2000. In addition, they borrowed the 2000's intake-tract design. On the 900, the intakes are extremely long, even extending into the airbox; downstream of the throttle body the ports get narrower too. Both features--long, narrowing intakes--heavily favor low-end and midrange torque. In fact, Kawasaki says the 900 pumps out the class's highest peak horsepower and torque: 53.6 bhp @ 6000 rpm and 60.5 lb.-ft. @ 3500 rpm.You can feel how successful they were every time you pull the wire on the 900 Classic. By their very nature, big-displacement V-twins (no matter what anyone says, 903cc is still a big displacement) tend to be torque monsters, and when you emphasize that trait as on the Vulcan 900, you get an engine that lunges forward most anytime you wind the throttle open. And with peak torque happening right at 3500 rpm--precisely 59.1 mph in top gear--passing requires little more from the rider than a lazily flicked right wrist. What's more, the 900 offers excellent fueling, with smooth, progressive throttle response, even off-idle. If anything, the 900 torque and power curves feel a little too flat. Sure, the Vulcan pulls plenty hard, but it pretty much always feels the same; there's no kick anywhere in the rpm band.