Drew Ruiz

Kawasaki's Z900RS Is Not a Record-Breaking Superbike, and That's Okay

First ride review on the 2018 Kawasaki Retro Sport

“Riding a Z1 in 1973 was like driving a Corvette when everyone else was driving Chevy LUVs.” —Bryon Farnsworth, Lead US Test Rider Kawasaki 1973–’76

In the early '70s, the Kawasaki Z1 was the bike to have. Setting 46 AMA and FIM speed records in 1973, the 903cc superbike was nicknamed the New York Steak because it was simply the biggest and the best. Now Kawasaki is bringing the heritage of the Z line back with '70s color schemes and more classic, upright styling paired with modern suspension, engine, and chassis components. While the styling and engine modifications all seem to make this bike more approachable, a higher price point, decrease in power, and abrupt, "switchy" throttle response might leave riders asking what it is they really want out of this bike.

2018 Kawasaki Z900RS Action
The 2018 Kawasaki Z900RS gets a 10 out of 10 for its good looks.Drew Ruiz

The Z900RS’s appearance is clean, simple and attractive. The engine has little contrast-cut fins to give it more of an air-cooled look (though it is liquid-cooled), and Z1 motifs on the clutch cover and other components pay homage to the classic model. Polished stainless exhaust are an appropriately vintage look for this bike, and the short upswept muffler is damn fine to look at—not to mention the sound when that 948cc inline-four winds up. It’s obvious that a lot of heart and soul went into designing this bike, and those who did the work really do have something to be proud of.

The name “Z900RS” might lead readers to believe this bike has more in common with the Z900 than it really does. This model has its own frame, easily distinguished by the more horizontal subframe and flatter seat. Less easily distinguished changes are the more relaxed 25.4-degree rake (vs. 24.5 on the Z900), shorter 3.5-inch trail (vs. 4.1) and longer 58.1-inch wheelbase (an inch longer). Shorter trail makes steering lighter, while the longer wheelbase helps stability. Other changes were modified engine internals, as well as upgraded suspension and braking.

2018 Kawasaki Z900RS Exhaust
Polished stainless exhaust on the 2018 Kawasaki Z900RS.Drew Ruiz

The goal was to make a bike that would allow riders to “slow down and enjoy the simple things in life” while also maintaining a capacity for aggressive riding. However, in an attempt to emphasize low- to midrange torque, Kawasaki traded the smooth throttling of the Z900 for a lurching, twitchy throttle that diminishes rider confidence and made it difficult for me to relax and “enjoy the simple things” while white-knuckling the handlebars and trying to rein it in.

2018 Kawasaki Z900RS
Morgan is shamefully excited about his new custom Veldt helmet, too.Drew Ruiz

The 948cc engine was reworked to provide more low-end power for riders who might have a hard time utilizing the top-end horsepower of the Z900. As usual, boosting bottom end takes some off the top, claimed peak output dropping from 125 hp down to a 111. A short first gear and taller sixth gear give you a sporty feeling off the line but also comfortable, lower-rpm cruising at freeway speeds. New cam profiles with shorter intake and exhaust duration look to build more power lower in the rev range, and compression was reduced from 11.8:1 to 10.8:1. Crankshaft flywheel mass has been increased by 12 percent to help smooth vibration. While all of this seems like it would mellow things out a bit, during real-world application the throttle felt more like an on/off switch than a smooth rheostat, and upshifting to drop revs and calm down the abrupt response left me wanting for even more low-end torque when I needed it.

2018 Kawasaki Z900RS Taillights
Iconic paint and shape of the tail section on the Z900RSDrew Ruiz

While cruising around town, the three-way-adjustable 41mm fork and two-way-adjustable Horizontal Back-Link rear suspension felt great. Small bumps disappeared, and it was soft enough for highway cruising but got a little springy if you hit anything other than smooth road in the turns. We didn’t adjust the damping on our short ride, but look forward to getting a test bike to experiment with suspension setting. That bouncy feeling paired with the overly aggressive throttle made it hard to ride aggressively and confidently, as it felt inconsistent and unpredictable.

2018 Kawasaki Z900RS Action
Morgan Gales taking the Z900RS through the urban jungle.Drew Ruiz

While I had initially blamed the throttle response on the low-to-mid range torque increase, it’s more likely a result of Euro 4 compliance. In order to reduce emissions, they map the bike for very little fuel at idle, making the roll onto throttle rather abrupt. I have reached out to Kawasaki’s reps for a more thorough explanation and will update the story with their response.

Dual semi-floating 300mm front petal disc brakes with four-piston monoblock calipers provide good stopping power and great feel at the lever. The single 250mm rear with its single-piston pin-slide caliper has plenty of bite as well and applies smoothly and easily. Really, the best thing about the brakes is that they are sporty, fit the character of the bike and won’t leave you wanting for more.

2018 Kawasaki Z900RS Gauges
Analog gauges on the Z900RS.Drew Ruiz

While Kawasaki calls this bike “retro,” it’s much more than that. Yes, you have a throwback paint scheme and that iconic tailsection, but the Z900RS is an absolutely modern motorcycle. Talking with Mike Vaughn, who was on Kawasaki’s new product development team from 1974–’76, he said, “I wouldn’t even call it retro. It just looks like a motorcycle again. They were starting to look like insects for a while there.”

And it’s true. What makes this retro? The polished pipes, flatter line between the tank and the seat, and a headlight that doesn’t look like it might turn into a Decepticon? Maybe this shift to more classic styling is just modern design cycling back to more minimal trends. Whether or not new riders will see relevance in the ’70s heritage of this model doesn’t matter because they’ll see a great-looking motorcycle regardless.

I can easily say the Z900RS is one of the best looking bikes of the year. From a performance perspective, the slightly relaxed steering geometry maintains nimble handling while better suiting the less aggressive nature of this model, and the brakes are smooth and effective. The ergonomics are comfortable and all the little aesthetic details are well thought out. Reworking the engine for more umph in the low-to-mid range makes a lot of sense for this model as well, but the messed up throttling makes it hard to enjoy. The goal of a more carefree ride is missed as the abrupt throttle causes the bike to pulse uncomfortably through the turns. Reworking fuel mapping would be a pretty easy aftermarket fix (though it ought to be right from the factory), and it would transform the entire feel of this machine. The design is stylish with a great blend of modern and retro, but it’s hard to justify less power with less effective delivery for $2,600 more. I was really hoping this would be the bike to get that perfect blend of design and performance, and it still has a shot if Kawasaki irons out those wrinkles in fueling.

2018 Kawasaki Z900RS Action
A beautiful throwback with comfortable ergos, but a little too twitchy of a throttle.Drew Ruiz

2018 Kawasaki Z900RS

  • Engine type: Liquid-cooled, DOHC inline-four
  • Displacement: 948cc
  • Seat height: 31.5 in.
  • Fuel capacity: 4.5 gal.
  • Claimed wet weight: 472 lb.
  • MSRP: $11,199