How They Compare
Engine
Challenging Suzuki's tried and true 650 V-twin motor is like jumping in the ring with Mike Tyson in his prime; you can pretty much count on getting your ass kicked despite slipping in a few good shots. The Gladius sports a 645cc V-twin that's been massaged with revised cams, crank and fuel mapping to put out 67 HP at the wheel. Unlike typical twins the Gladius is extremely smooth and more akin to a V-four in terms of ridability. This makes it easy to live with; no clutch slipping or snatchiness away from traffic lights and no lurching from as low in the revs as 1800 RPM.
The Kawasaki ER-6n feels pretty familiar thanks to the Ninja 650-it's the exact same motor. It works a bit better in the sportier Ninja package though because you sort of expect to rev a sportbike, while with the ER-6n we'd prefer a smoother low end. Below 2000 RPM the 63 HP parallel twin coughs its guts out and can't chug the lug. Instead, it finds its groove while already on the move and slightly into the rev band. Once into the lower midrange the engine comes alive and has torque-a-plenty to easily pull the front wheel straight up in second gear, but it's the extreme low end that is the most distinguishable between the Suzuki and Kawasaki. The Gladius pulls away seamlessly while the ER-6n needs to take a deep breath before finding its legs. While that might seem insignificant to many of us, it's actually a crucial concern for newer riders.
Winner: Suzuki
Chassis
Both bikes utilize a steel trellis frame and 41mm forks, but the similarities stop there. Like a beauty with no brains, the excitement of a great motor wears off pretty quickly if there's nothing to back it up. Such is the fate for the Gladius because the chassis is really this bike's biggest shortcoming. "Ground clearance" is the oxymoron of the day because the Suzuki's peg feelers grind away with very little lean angle. While the steady scraping might do wonders for your ego it offers little in terms of performance-we all know that once the feelers are down the next in line will be harder, less mobile parts.
Through brisk sweeping corners the Gladius gets upset and takes its time to regain composure, and when the peg is gently skimming the road surface the last thing you want is the bike bouncing up and down. The same is true when navigating over bumps on the freeway (like those common dips over bridge joints). The rear shock bottoms easily and it can unsettle the entire bike into a flexing swagger that's unnerving at best.
The ER-6n manages road irregularities with much more competence though, and its sporting tendencies are immediately apparent through significantly better ground clearance (at the slight cost of leg room comfort) and a more composed chassis over rough surfaces. Bumpy country roads needn't be feared on the Kawasaki because it blends balance and comfort with just the right mix.
Winner: ER-6N
Brakes
Let's get one thing straight-both of these bikes are in desperate need of brake upgrades. Never should the rear brake feel similar in power to the front, but that's just the case here, sadly. Not to worry, because there are some simple and inexpensive solutions.
Loser: both
Style
The naked SV650 was discontinued, but the Gladius slots in its place and has cool style updates while retaining the beloved 650 V-twin engine. So why have so many enthusiasts formed strong negative opinions about its looks? We're not sure, and all agreed that it actually looks pretty cool. The chrome bars and mirrors are accompanied by a host of cool parts, the most impressive being the easy to read gauge cluster. The Gladius has a unique look, and it's not just a boring old naked SV.
OK, so the ER-6n looks like the Ninja 650's dorky brother, but compared to the Gladius it's pretty rough and tough. There's certainly nothing "girly" about the Kawasaki (which seems to be the biggest complaint about the Gladius). The ER-6n does suffer comparisons to several members of the insect world, most notably the grasshopper. Is that a bad thing? Not if you like bugs...
Winner: Tie