2009 Naked Middleweight Comparison

Kawasaki ER-6n vs. Suzuki Gladius: Six of one, half dozen of another


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What brought you to motorcycling? Maybe you grew up riding ‘cause your old man rode, so it was only natural you would, too. Or perhaps you came to the two-wheeled world a bit later in life, either out necessity for affordable transport or because a friend talked you into taking a ride on the back of their bike despite your previously having no interest in riding. You might even be one of the many recent moto virgins who finally reached a point in life where years of squirreling away enough discretionary coin finally granted access to two wheels.

Of the various paths that brought us to motorcycling, one common factor keeps us here: fun!  The fun factor is either what first wooed us to bikes or, like a bad drug addiction that you wouldn’t have unless a “friend” introduced you, it’s what kept you hooked from the first taste.

If you’re in the market looking for that next injection of bike or have completed some rider training and are ready for bike numero uno, boy, have we got a couple fun bags for you! To ice the cake, these new middleweight machines even offer some sensibility to go with the laughs.

The 2009 Kawasaki ER-6n and 2009 Suzuki Gladius. Every man’s dream: naked Twins!

Twofer Twins

Gladius and ER-6n Specs Comparo

Though Kawasaki’s ER-6n has been available in Europe since 2006, it’s finally made it to U.S. shores in a newly revised form for 2009. The ER is the fraternal twin to the Ninja 650R, the bike the U.S. got in 2006 and is also updated for ’09. It shares identical chassis and engine specs (just as they did in ‘06) to the Ninja but does away with virtually all bodywork, save for minimalist radiator shrouds that house turn signals, and a prominent headlamp that functions somewhat like a flyscreen.

This year marks the first revision to both the ER-6n and Ninja 650R. In our review of the 2009 ER, Kevin “Canadian Bacon” Duke, educated us with the news that Kawasaki smoothed out engine vibes inherent in the parallel-Twin engine architecture. Team Green reduced buzz by way of rubber bushings in the upper-rear engine mounts, rubber mounts for the steel handlebar, rubber-covered footpegs, and even included rubber mounts for the pillion grab rails. Other updates include revised frame stiffness, a lighter catalytic converter, and reshaped fuel tank and seat that are more welcoming of shorter riders. The Ninja 650R also received updated bodywork styling, and both bikes share a new instrument cluster.

Whether by a need to capitalize on shifting market trends or some other undisclosed logic, Suzuki laid to rest the venerable SV650, a bike that quickly reached cult status after its 1999 introduction. Oh, the wailing and gnashing of teeth that must’ve happened amongst the Suzuki loyal when they learned the naked SV650 was no more for 2009 (a fully faired SV650SF remains in the lineup at $6,999). Although Suzuki refuses to refer to the 2009 Gladius as a “replacement” for the SV650, the fact that the Gladius is powered by a revised and updated V-Twin that made the SV so popular makes it hard not to see this new naked sportster as an SV reborn.

Both new middleweights put the naked twist on recent model platforms.

We learned during the Gladius’ U.S. press introduction that its 90-degree V-Twin sees numerous improvements in the engine room with things like: higher lift cams; single rather than dual valve springs; the same 10-hole injector throttle bodies as found on the GSX-R600 and 750; longer air intake funnels in two different lengths for improved mid-range; use of Suzuki’s Idle Speed Control (ISC) system integrated into the throttle body rather than externally mounted – a first ever on any Suzuki street bike; a new compact mid-ship exhaust (similar to the ER’s); two Iridium-tip spark plugs per cylinder complete the engine update package.

Carrying the capable engine is the work of a truly new-for-the-Gladius steel-tube trellis-type frame mated to a box-section steel swingarm.  The styling of this new middleweight is purely unfaired with only two small accent pieces dressing up a re-designed radiator, and a headlight and instrument panel styled together make for a look equally unique but different from the ER-6n.

Two peas in a pod

Both bikes are liquid-cooled, DOHC, 4-valve-per-cylinder, and both are called a 650 by their respective makers, but the ER squeezes out a skosh more in displacement at 649cc  (83.0 x 60.0mm) in its parallel-Twin, while the Suzuki’s 90-degree Vee is a true 645cc (81.0 x 62.6mm). Compression ratios are scary close, too, with the ER at 11.3:1 and the Gladius with 11.5:1.  But the similarities don’t end there…

Displacement is, for all intents, identical, and in virtually every way, so is engine performance.

There are two different types of engines at work here, but a quick scan of dyno results courtesy of Mickey Cohen Motorsports will make you do a double take. The graphic representation of horsepower and torque looks almost as if one bike was dyno’d twice. It’s a neck and neck race in hp, as both bikes are amazingly well-matched until about the 7,400 rpm range where the Gladius starts sprinting for a peak hp reading of 67.9 at 8,500 rpm, a full 5 more peak hp than the ER. The differences in peak torque are even closer, separated by just a hair over one foot-pound (44.2 v. 43.1 ft-lbs) in favor of the Gladius, but more important here is that the ER hangs tight until the last minute, as you can see by the dyno chart.

The numbers game is almost too close to call at times, but engine character is a different story. The Gladius’ Vee configuration provides that traditional grunty bottom-end feel, while the (mostly) vertical action of the Kawi’s side-by-side pistons gives the impression of a revy in-line sportbike motor. Neither of these bikes will leave 99% of their owners pining for more power. Both wheelie first gear easily with a little finessing of the clutch and will dig you out of a slow corner in no time.

Fueling and throttle response are good on both motorcycles, however, the ER exhibits a “hint of abruptness during throttle reapplication,” as Kevin dutifully points out, but then smoothes out immediately thereafter. Transmission and clutch action is more of the same. The ER’s trouble-free six-speed uses Kawasaki’s neutral-finder design that eases access to neutral when stopped, and rowing through the slick Suzi gearbox is a shifting pleasure.

With such a thin line separating nearly every aspect of the ER and Gladius, one is always nipping the heels of the other.

Suspension is one area where manufacturers can cut costs in order to keep retail figures low. Yet in the case of this pair o’ Twins, cutting costs doesn’t necessarily equal crap springy parts.

Front suspension consists of 41mm fork tubes; the ER’s is un-adjustable while the Gladius offers spring preload. Rear suspension is where the bikes differ slightly, with the ER retaining the easy-to-access preload-adjustable linkage-less shock from the Ninja 650R, while the Suzuki’s shock, also preload adjustable, employs a more traditional linkage system. Neither bike’s suspension will have you mistaking them for supersport repli-racers, as both tend to be on the soft side in order “to accommodate lighter riders and to provide a cushy ride,” as Kevin noted. But in light of their intended target audience, this makes perfect sense. However, we feel Suzuki’s use of linkage in mating the shock to the swingarm was good choice, as it offers a more linear response and better absorption of the rough stuff.

Despite the ER’s steering geometry appearing livelier on paper (55.3 v. 56.9 inch wheelbase; 24.5 v. 25.0 degree rake, 4.0 v. 4.17 inches trail), there was little if anything to separate these two in terms of a superior handler. Each bike’s upright handlebar, though a little narrow feeling, provides good steering leverage. Pushed hard enough their budget suspension will protest with squirms and wiggles, but right up to that point, each bike had noteworthy stability. And of course there was no discerning the Suzuki’s minor advantage in claimed curb weight (446 v. 449 lbs).

Each naked Twin has friendly ergonomics, welcoming riders of different skill levels and physical stature.

Identical tire sizes (120/70 x 17 front, 160/60 x 17 rear) and tire brand only add to the difficulty in finding areas where one bike differs vastly from the other. The ER rolls on Dunlop’s sport-touring-oriented Roadsmart model, while the Gladius spins a set Qualifiers, also made by Dunlop. The slight extra grip of the Qualifiers couldn’t be exploited on the Gladius, as it has less cornering clearance than the ER. Long peg feelers keep the right-side exhaust from scraping the ground, also limiting lean angle on the left. 

The Gladius and ER-6n further mimic each other with braking componentry, as both use dual two-piston sliding-pin calipers. The Kawi spins bigger (300 v. 290mm) petal-type rotors, but that doesn’t necessarily equate to extra power in this case. Overall braking power is pretty well matched, but the Gladius offers noticeably better feel at the lever, while the Kawasaki’s binders felt a touch more wooden (numb) than we prefer despite revisions to the master cylinder for ‘09. Perhaps a simple swap-out of pad material would resolve this same issue of poor feel we noted on the Ninja 650R during its 2006 model launch.

Ergonomically, both bikes attempt to achieve the same goal of an upright, open riding position that should appeal to an array of enthusiasts, from the seasoned rider to the daily commuter to the first time rider. Mission accomplished on each.

Nevertheless, this is where we start to see some disparity. The ER’s designers not only moved its new seat (29.7 v. 30.9 inches) closer to the ground, they did so without sacrificing saddle comfort. Where the ER’s seat is wide and cushy without being overly soft, the Gladius’ relatively low seat was partly achieved (shortened front suspension also aids in a seat lower than on the SV650) at the expense of a saddle that’s mouse-pad thin. On the other hand, the ER’s higher ground clearance pays a moderately negative dividend in the form of little less room between footpeg and seat. To achieve minimum heights, both seats slope forward to the tank junction which reduces long-range comfort.

Wind protection from these mostly fairing-less bikes is limited as you would expect, but the rather large, if not odd, shaped headlights do a good job of taking wind pressure off the rider’s chest. Even at 80 mph we were able to ride comfortably with limited wind buffeting.

Instrumentation, like the styling of these two mid-weight steeds, is largely a matter of taste, but we couldn’t help but prefer the Suzuki’s prominently displayed analog tach joined by an easily read LCD speed readout and gear position indicator. The Kawi’s cluster matches the bike’s Euro-modern style; we liked the white-faced speedo, but its narrow shape and smaller numbers along with the equally narrow LCD bar-graph tachometer proved to be harder to read while bombing down the road. Furthermore, it lacks a gear position indicator, something we’d expect to be an important item for the intended market.

Fit ‘n’ finish, like just about everything else, is a game of tit-for-tat. The ER’s mirrors have a fresher, more up-to-date shape, but don’t necessarily offer a better view than the Suzuki’s tried-and-true chrome teardrop units. We like the shock spring color-matched to the rest of the bodywork on the ER, and its LED taillight is substantially brighter than the incandescent bulb the Gladius employs. However, we easily see where one person could appreciate the Suzuki’s flowing, smooth lines over the more angular shapes on the ER that lend to an overall more mechanical look.

Can you flip a one-sided coin?

What we have with the $6,399 Kawasaki ER-6n and $6,899 Suzuki Gladius are two bikes that make it very hard for a prospective buyer to choose one over the other. One bike’s shortcoming may be made up for by performing better in another area the contender can’t quite cover.

The ER’s saddle is a little lower and better padded, its exhaust is less visually obtrusive, its ergos are a smidge friendlier, and its parallel Twin feels racier. The Gladius’ front suspension offers preload adjustment and its shock performs a tad better; its wasp-waisted shape makes it feel narrow and light; its brakes provide more feel; fueling is a touch smoother just off idle, and its updated V-Twin sourced from the venerable SV650 has a modest power advantage.

No matter what flavor you choose, the ER-6n or Gladius are heaps of fun whether you’re a salty riding veteran or looking for that first bike.

We could go on like this until we’re down to the smallest nuts and bolts. Suffice it to say that choosing one over the other will likely come down to a matter of personal taste. But whatever way you’re leaning, know that both bikes are fun to ride, and they’re fun to ride because they make riding easy.

Each will serve well as a first bike or as a daily workhorse that morphs into a canyon-eating, harasser-of-bigger-bikes sleeper on the weekend. The choice is yours… 

Related Reading
2009 Kawasaki ER-6n Review
2009 Suzuki Gladius Review
All Things Suzuki on Motorcycle.com
All Things Kawasaki on Motorcycle.com
All Standard Motorcycles Reviews on Motorcycle.com

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