Since both engines have fuel injection, they start immediately and respond readily to throttle, hot or cold. Both also have crisp throttle response, though the Suzuki occasionally reacts somewhat abruptly to throttle-position changes. While the 805cc Suzuki is quicker away when the light changes, the 900 Classic's added displacement and broader torque curve soon catch up. In all-out races, the 903cc Kawasaki has the edge. It also has more grunt in reserve when you roll on without getting the revs up. This is most noticeable when you're carrying a passenger or passing on a hill. The Suzuki needs a downshift and a bit more rpm to keep up. If you like to ride at low rpm, the Vulcan 900's power will please you a bit more. If you prefer an engine that revs freely, the Boulevard C50 motor will be more your speed.
Both drivetrains are smooth and easy to manage. The clutches are light and engage predictably. Gear throws on either motorcycle's heel-toe shifter are light and positive, and finding neutral is easy, though the Vulcan's automatic neutral finder gives it a slight edge. Ratio staging leaves no complaint on either bike, although adding a sixth speed would be a solid plus on both machines. The Suzuki seems just a bit busier on the highway, but that's probably due to its dual-crankpin layout, as its top gear is fairly tall. The C50's shaft final drive doesn't add any significant lash to the drivetrain, nor does it create much jacking. The Vulcan's belt-drive power train also doesn't create any such issues and is a bit lighter and cleaner, although it has just a small amount of whine.
Both bikes are capable of returning 40 mpg or better on the highway, but the C50 approached 50 mpg more frequently than the 900 Classic. However, its extra 1.2 gallons of fuel capacity gives the Vulcan a range comparable to the Boulevard's. With EFI, neither bike has a reserve system, just a warning light that signals when you're working on your last gallon. The fact that the Vulcan 900's speedometer and odometer/tripmeter are about twice as optimistic (almost eight percent versus four) as the C50's may have you believing you've gone farther, faster and gotten better fuel mileage than you actually have.
In the end, neither of these motorcycles eclipses the other, although they do stand above the other current cruisers in this 750 to 1000cc category. (To be fair, we haven't ridden Honda's new-for-2007 shaft-driven Shadow Spirit 750.) We think the presence of a good dealer would be reason enough for picking one over the other. That said, each bike has its strengths.
If you buy for looks, we suspect the Vulcan 900 will be your choice. It's also the better pick if your plans include riding frequently with a passenger or touring (for which we'd suggest the LT version). If you expect most of your riding to be urban or on winding roads, then the Boulevard C50 is the better choice. It's also the more economical player, not only because of its lower buy-in, but also because it gets better fuel mileage. There are also no major changes we'd want to make to the C50, but we would want a better rear shock on the Vulcan 900 and probably a new seat for touring. Nevertheless, either bike can happily manage any motorcycling mission in style.
The bottom line is that both of these motorcycles are great cruisers-maybe even the perfect cruisers. Notice we didn't include "middleweight" or any other size qualifier in that statement. The Boulevard C50 and the Vulcan 900 Classic are simply great motorcycles to ride, no matter what the mission. Wield the Suzuki Boulevard M109R on a cross-country odyssey? Only if a personal chiropractor comes along. Wrestle the notchy 900-pound Kawasaki Vulcan 2000 around downtown L.A.? No thanks. But press the Boulevard C50 or the Vulcan 900 into those situations, or a dance down a wriggling road, and the ride becomes a hoot, not a headache. There's enough power and size here to comfortably and confidently set off after the horizon with a passenger, but their reduced bulk makes them much more fun than bigger bikes when maneuvering.
The Kawasaki Vulcan 900 Classic and Suzuki Boulevard C50 are bikes we've already been recommending frequently to readers asking for buying advice. That's not just because they offer exceptional cruising value for the money. Come visit our garage almost any evening or weekend while we're out. You'll probably find the big, stuff-of-dreams mega-twins languishing there unridden while these two "middleweights" are out making serious miles with us. Unless power or the ability to brag about the size of your piston is your primary yardstick, these motorcycle are simply better and more fun to ride.