The Big Test: 2004 Yamaha Road Star 1700, Honda VTX 1800N, And Kawasaki V2K

Harley-Davidson
Suggested retail price: $26,595 ($27.095 California)
Warranty: 24 months, unlimited miles
Engine: Air-cooled 45-degree OHV V-twin, two valves per cylinder
Displacement, bore x stroke: 1690cc, 92.25 x 110.8mm
Carburetion: EFI, 45mm bore
Transmission: Wet, multiplate clutch, 5 speeds
Wet weight: 848 lb.
Wheelbase: 63.5 in.
Seat height: 27.1 in.
Rake/trail: 26 degrees/6.2 in.
Front tire: MT90B16 Dunlop/Harley D402F tubeless
Rear tire: MU85B16 Dunlop/Harley D402 tubeless
Front brake: 2, 11.5-in. discs, 4-piston calipers
Rear brake: 11.5-in. disc, 4-piston caliper
Front suspension: 41mm stanchions, 4.6 in travel
Rear suspension: Dual dampers, 2.2 in. travel, adjustable for air pressure
Fuel capacity: 5.0 gal.
Fuel mileage: 35.3 mpg avg.
Quarter-mile performance: 13.09 sec., 98.3 mph

Engine Tech: Thinking Big
Honda
Aside from size, the VTX 1800's engine is an almost typical Honda cruiser V-twin. That is, it employs Shadow-like technology in the split crankpins-the connecting rods meet the crank at two slightly skewed positions, not side by side as on the other V-twins here-which helps reduce engine vibration significantly. (Split pins create other types of vibration in smaller amounts, but aren't nearly as annoying as the large primary imbalance of a narrow-angle-in this case 52-degree-V-twin.) This scheme makes the engine act more like a 90-degree V-twin, which has perfect primary balance. What vibration escapes the split crankpins and the massive, 41-pound flywheel assembly is counteracted by a gear-driven counterbalancer, while driveline shocks are taken up by three sets of vibration dampers, one on the crank end and two in the clutch assembly.

Twin-plug combustion chambers are fed by three valves each, two intake and one exhaust, long a Honda hallmark for engines intended to produce little high-rpm power. Unlike the Kawasaki and Yamaha, the Honda uses chain-driven single overhead cams. Generous cooling fins suggest otherwise, but the VTX is in fact liquid-cooled. If you're wondering, the actual redline is 5750 rpm.

Kawasaki
You'd think Kawasaki would pull out all the stops in making the biggest production V-twin going, and you'd be right. With a 103mm bore and 123.2mm stroke, the Vulcan's engine is not just the largest production V-twin made, it's the most undersquare of this bunch as well, with a bore/stroke ratio of 0.83:1. (Honda's is less undersquare at 0.89:1; the Yamaha is in the middle at 0.85:1. A typical sportbike's ratio is quite oversquare, at around 1.5:1.) Generally, a long-stroke engine builds torque strong and fast, as the Vulcan does with a vengeance. (There's a 16.8 foot-pound gap from the Kawasaki's peak at 121.4 foot-pounds and the Honda's at 104.6.) Inside those massive heads are four valves per cylinder-chosen most likely as much to provide additional heat paths through the valves as for the breathing ability of this configuration-operated by a total of four pushrods and two cams located in the right engine chest, as Harleys have done since about forever.

Pushrods? On a brand-new design? It makes sense, actually, if you intend to keep the engine as short as possible, a task already made tougher by the long stroke. Besides, the rev limit on this engine (actually 5000 rpm) is set by maximum piston speed, which in turn dictates a redline well within the capabilities of a modern pushrod valve train. Hydraulic lash adjusters make this setup maintenance-free also. A gear-driven counterbalancer helps flatten the considerable vibes inherent in this design.

Yamaha
On a bike intended to house a classical rendition of the V-twin cruiser engine, the Road Star's mildly tuned powerplant makes a bit of sense. For 2004, Yamaha increased the bore to meet Warrior-spec, at 97mm, giving a total displacement of 1670cc. Yes, it's the smallest engine here, but that's not why it lags behind the others in power. Simply put, the Road Star's 48-degree, air-cooled V-twin has very mild cam timing, four small valves per cylinder, and must breathe through a single 40mm carburetor. That's partly why the Road Star's engine, at 61.1 horsepower and 93.1 foot-pounds of torque, dramatically lags behind even its Warrior brother, which, thanks to fuel injection, hotter cams and a freer-breathing exhaust system, pounds out 76.3 hp and 97.9 foot-pounds of torque, and has a 1000-rpm-higher redline to boot. Yamaha is keenly aware of the gap, and we're fairly sure there's work afoot to remedy this situation.