Kawasaki’s fifth supercharged H2 model comes out swinging on the high banks.

By John L. Stein, CycleworldFebruary 25, 2020

It was inevitable, the transference of Kawasaki’s supercharged H2 technology to new models. And so, observe the 2020 Z H2, the world’s first production supercharged naked bike. Readers who might have dismissed the supercharged Ninja H2, H2 Carbon, track-spec H2R, and H2 SX SE+ sport-tourer as little more than hyperkinetic yuppie trinkets may be surprised that the Z H2 is actually a very good standard motorcycle.

Yes, the power is terrific. Its H2 SX-based 998cc DOHC four is rated at 200 hp at 10,500 rpm—and with 14.7 pounds of boost pumped in, the Z H2 is perfectly described by The J. Geils Band’s as a “rage in the cage.“ (Except in this case the cage is a high-tensile steel frame.)

And where on God’s green earth would you use this kind of power? Logical places are El Mirage dry lake, the Bonneville Salt Flats, a random unoccupied runway…or a speedway oval. Yep. Kawasaki chose Las Vegas Motor Speedway as the launch point for international press in early February 2020, and Cycle World nabbed a spot in wave 1. The Speedway’s oval is 1.5 miles around, with 20-degree banked turns. Not as long and steep as Daytona or Talladega but useful for (at least partly) containing this hellcat at full throttle.

Some brief guidance about piloting a 200-hp bike around a NASCAR oval: Pit-squids need not apply, nor should the timid, Mr. Magoo, the politically correct, the ham-fisted, nor the nearsighted. The Z H2 presents as expected: a naked literbike with genial open seating and cockpit dimensions; a wide, low-rise handlebar; a fat fuel tank (narrowed below and behind for the knees, thanks much); and a modestly padded seat. And. Huge. Freaking. Power!

All About That Boost

Tagging the starter switch gives little audible evidence the motor contains an aluminum supercharger impeller that can spin more than 110,000 rpm via a planetary-gear overdrive. And whenever the engine’s running, that supercharger is turning and burning. Nervous much?

Thanks to the clutch’s assist function (essentially, it mechanically locks during acceleration), which permits lighter springs, the lever pull is moderate. And built to handle a claimed 101 pound-feet of torque, the dog-ring six-speed gearbox is—and feels—robust. A solid clunk and a jolt delivers first gear, and easing the clutch out with the big adjustable lever gets the bike underway. Perhaps it was a simple cable adjustment for the ride-by-wire throttle on our test unit, but we felt the twistgrip needs a bit less slack just off the stop.

From here on, with its dual balancers the Z H2 engine is bliss. Almost unfathomably smooth heading toward its 12,000-rpm redline with just a few minor tingly spots in the middle, it is a marvel of engineering. As well, the powerband is magical. This is not a fussy motorcycle to ride—not a Jekyll and Hyde proposition. Once above idle, the throttle is virtually rheostatic in that you simply dial up the power you want and the machine delivers. If you will, it is almost electric in its smoothness and willingness. Take that, LiveWire!

Naked And Unafraid

Our first exposure to the bike in the flesh, or rather metal and plastic, happened in the Speedway garages. Just a handful of green-frame models intended for the US market were among many more red-frame models built for Europe. With most journalists coming from overseas, the red-frame bikes thus became our test units, with the green-frames reserved more for photography.

Kawasaki’s “sugomi” design language for the growing Z range deems that design evolves with engineering. This has already brought us such two-wheeled tirades as the Z1000 with its praying-mantis beak and Star Wars exhausts, and now the more agreeable Z H2. Although edgy, the Z H2 actually presents as less radical than the H2 from which it stems. But so what? Looks count only so much when you’re in motion, and so we’ll neither support nor reject the Z H2 visually. That’s your deal; we’re more interested in how the bike works and how the bodywork integrates functionally.

Real Steel

The steel trellis frame architecturally is similar to the H2 SX, except that it uses a double-sided cast-aluminum swingarm instead of the single-sided swingarm on other H2 models. As Kawasaki’s engineering team explained, this has more to do with the Z H2’s dual mission as a member of the “Z family” and as a streetbike, rather than a hyperbike. Adding perspective here, the new Z H2 becomes the top of Kawasaki‘s growing Z model range, which starts with the mini Z125 Pro, extends through Z400, Z650, Z900, and retro Z900RS, before arriving at this supercharged newbie. All of those bikes have double-sided swingarms, and so the Z H2 follows suit.

The adjustable suspension (KECS in Kawasaki parlance) includes a Showa Big Piston Separate Function fork and Uni-Trak rear with Showa coilover damper. Tunable for spring preload, compression, and rebound damping, the suspension felt great on our first ride location, the Speedway’s external road course, and later on the oval, where speeds climbed substantially. However, on day 2’s long road ride, which involved plenty of low-speed work as well as interstate, the ride proved choppy. It’s likely that time spent dialing in settings would make it more agreeable here, but the likely outcome is that the Z H2 simply has a firm ride. Better this though, instead of wallowing around.

Freeze Frame

We got our shot on the first morning of the launch, on the road course outside the Speedway oval. This 2.4-mile circuit is flat, flat, and more flat, featuring 14 turns from a hairpin up to about 100 mph. Unfortunately, the morning air temperature was 42 degrees Fahrenheit, making wind chill at “the ton” a brisk 24.7 degrees Fahrenheit. This rendered hands frozen after 15 to 20 minutes. But no matter, as the Pirelli Rosso III tires (120/70-17 front, 190/55-17 rear) barely seemed affected by this; with a high silica content, they are designed for all-weather use.

As well, the smooth, race-quality surface didn’t challenge the suspension particularly. What this multifaceted road course did do, however, was test the bike’s steering geometry, cockpit ergonomics, braking—and supercharged acceleration.

Fleet Of Foot

With 24.9 degrees of steering rake, 4.1 inches of steering trail, and a 57.3-inch wheelbase, the 527-pound (claimed) Z H2 is a ready partner for anything you’ll find on the street or a trackday. The bike is nimble from the moment you lift your feet and roll away, through any style of corners you’ll find, and remains stable as fast as you dare go.

Our only small handling gripe came under a peculiar situation later in the day, where the Speedway’s banking met the flat chicane surface at an angle. Here, the bike was leaned over while encountering the sudden camber change. This momentarily steepened the steering angle, added steering force, and caused the machine to stand up. With no other bikes to ride under the same circumstance it’s impossible to know whether other machines might be similarly triggered, but we feel this odd dynamic trait is not any fault of the Z H2’s otherwise agreeable geometry. It’s just the track, Jack.

Basic Brakes

Brakes include radial-mounted Brembo four-piston Monoblock front calipers and a Nissin master cylinder; in back is a two-piston caliper. Standard ABS integrates electronically with the engine ECU to reduce lever pulsing and increase precision. The brakes are strong, able to haul the Z H2 down from terrific speeds repeatedly, but they do require significant lever effort. This is fine to the generalist or Sunday rider because hair-trigger superbike brakes can be alarming or abrupt. We would’ve liked a bit more initial bite and a bit less lever effort but the systems are perfectly adequate for a naked bike, and it’s unlikely we’d elect to change them on our own Z H2, if we ponied up for one.

Puffer Power

Kawasaki is proud of its supercharger technology, and as the only motorcycle manufacturer offering it, they should be. The little 2.7-inch, machined aluminum, multi-blade impeller develops a maximum of 14.7 psi of boost, or just over one bar in Euro-speak. The H2 and H2R develop more: 20.5 psi.

The engine really comes alive at about 8,000 rpm; from here north to the rev limiter it’s an absolute tiger. So much so that the onboard five-axis Bosch IMU driving the bike’s anti-wheelie function becomes crucial in keeping the front end down so you can accelerate smoothly away from corner exits. Even so, this bike has so much grunt, we found it essential to get pointed straight before squeezing the trigger hard. To paraphrase Barbara Billingsley in Airplane: “Fool, don’t make this your first bike!”

A couple of sessions in the frigid road-course conditions couldn’t sate our desire to ride the Z H2 faster, but they did provide an accurate first feel of its essential character, which is right fine. Highs: an incredibly smooth engine, a wonderfully flexible powerband, and an insane top-end charge. Also, agreeable handling and ergonomics just right for combined street/track work. Lows: The quickshifter isn’t smooth as it should be, and the brakes aren’t exactly race spec. Further, the back-force-limiting (slipper) clutch still allowed some rear-wheel hop on hard deceleration if we hurried the downshifts.

Oval Meister

In the afternoon we moved to the NASCAR oval inside Las Vegas Motor Speedway, which Kawasaki had set up with a dogleg chicane at the start-finish line. This is actually a good thing, exposing test riders to more than just the bike’s raw speed potential.

The chicane meant that about 95 percent of each lap on the oval could proceed at the fastest pace riders could possibly stand before getting hard on the brakes, flipping through the chicane, and then back on the gas. This feature was intentionally interruptive, but in a positive way because apart from giving the brakes and electronics a workout, it gave the Pirelli Rosso III street tires a chance to cool on each lap.

While stacking up laps, our speeds climbed: first at perhaps 120 mph in the turns and then gradually closer to 135 mph; then the bike first reaching the mid-140s at the end of the back straight and finally more than 160 mph here. It’s exciting to find the turn 3 banking coming up and knowing that you’re really not going to carry 160 mph into it. Instead, we dropped a gear and slung around it joyously lap after lap, chin hovering over the triple clamp, left knee out for aero drag, right knee tucked under the trellis frame and pushing left, and right hand pulling back on the bar slightly. It might be possible to go full-chat around the oval on the Z H2, but the penalty for misinterpreting what’s possible could be severe. Easy there, Laddie!

Steady Zeddie

What’s important here is that even under such fairytale (or maybe, alarming?) conditions, the Z H2 behaved really well. In fact, even such an anomalous dynamic request as tipping the machine into a 20-degree banking while scrubbing off huge speed at the top of fifth gear was met with only the briefest—and not very unsettling—wiggle at the back end; no problems there. In a way then, riding an oval fast reminded us of scuba diving or hang gliding: You know you’re potentially in great peril, and yet by maintaining composure, smarts, and control you’re perfectly safe. Ovals all around!

The braking zone for the Speedway’s chicane, and the few turns that led riders back onto the oval, were a great exhibition point for the supercharged engine’s aural virtue-signaling—a unique tweeting or fluttering emanating from the blow-off valve attached to the intake plenum. On trailing throttle, an ECU allows excessive boost to bleed through this valve into a vent near the rider’s left knee. The sound is like Flipper chattering or a whip-poor-will singing, and it’s unmistakable from anything else in motorcycling. Well done, Kawasaki.

Drudgery Report

Our second ride day found us on a lazy walkabout (or rather, rideabout) through the Valley of Fire State Park, where the speed limit is a mere 35 mph. Amazingly, the Z H2 motor is perfectly happy to burble along in sixth gear at this pace, just as it was to rage past 160 mph. No one would recommend trawling the Z H2 in sixth gear only, of course; this side narrative is simply an illustration of how flexible the engine truly is.

A few notes about the Z H2’s tunability are in order here. Four settings are available for the engine and chassis operating parameters: Rain, Road, and Sport presets; and customizable Rider, wherein traction control and power output can be individually adjusted. With little time to spend dialing things in, we ran the Z H2 on the road course and oval in Sport, and then on the street ride in Road, and left it at that. As a nice touch, Rider mode functions can be modified via your smartphone’s Bluetooth function and the free Rideology The App.

Other selectable display readouts include average speed, lean angle, boost pressure, average fuel economy, and more. And BTW, we saw an average of 37.5 mpg on one part of our Valley of Fire ride, the highest number noted during our two days with the bike.

Let’s Get Physical

It puzzled us initially, why the supercharged engine lacks an intercooler, because most turbocharged and supercharged cars use them to reduce the compressed air’s temperature before it reaches the intake plenum. The reason why is Physics 101: Air heats up when compressed quickly. And as to why piping the pressured air through an intercooler (aka heat exchanger) prior to it getting to the engine is important: Cooler air is denser; denser air contains more oxygen within a given volume; and more oxygen allows injecting more fuel, which makes more power.

So…how come no intercooler? According to Kawasaki engineers: 1) The H2 engine package was designed as a supercharged mill; 2) The aluminum intake plenum adequately absorbs heat; 3) Special oil jets cool internal surfaces subjected to high heat; and 4) The sophisticated aluminum impeller design helps reduce temperatures.

Interestingly, engineers declined to state the plenum air temperature when the bike’s making peak power on the dyno, and instead suggested we check the boost temperature readout on the instrument panel, accessible by toggling buttons on the left handlebar. So we did.

Some Like It Hot

How high would you suspect the boost air temperature might get on a non-intercooled supercharged engine? As a baseline, Kawasaki engineers said the normally aspirated ZX-10R’s plenum temperature would stay approximately ambient, meaning outside air temperature. So, on our way back to the Speedway from the Valley of Fire, on the interstate we pushed the Z H2 engine hard near redline (approximately 10,000 rpm for several miles) until the boost temperature stopped climbing. At this point, we observed an astonishing 239 degrees Fahrenheit with an outside air temperature of 57 degrees Fahrenheit.

For those who read bike magazines in high school instead of studying, water boils at 212 degrees Fahrenheit at sea level. Which means, the Z H2 plenum temps can reach some kind of hot. But why not intercede, engineering-wise? We asked Ralph Hudson, whose turbocharged and ice-water intercooled GSX-R1000 ran 307 mph in Bolivia, an FIM world record for a sit-on bike. There, the induction air temperature downstream of the turbo was 200 degrees Fahrenheit, but just 70 degrees Fahrenheit at the outflow of the intercooler. Ideal, no? But that drop required 62 pounds of intercooler, water pump, ice, water, and ungainly packaging. That’s ¡no bueno! for a production streetbike. Which means: The Z H2’s hot-box issue is what it is simply because it’s simpler, tidier, lighter, and cheaper that way. And the motor can handle it.

All told, we really like the naked Z H2, and think you will too. What’s not to like? A more comfortable chassis with hyperbike underpinnings makes for an H2 that’s accessible for the masses. Now go boost and roost.

2020 Kawasaki Z H2 Specifications

MSRP	$17,000
Engine	998cc, DOHC, liquid-cooled, supercharged inline-four
Bore x Stroke	76.0 x 55.0mm
Transmission/Final Drive	6-speed/chain
Claimed Horsepower	200 hp @ 10,500 rpm
Claimed Torque	101 lb.-ft. @ 8,500 rpm
Fuel System	DFI w/ 36mm throttle bodies
Clutch	Wet, multi-plate assist and slipper clutch
Engine Management/Ignition	TCBI w/ digital advance
Frame	Steel trellis
Front Suspension	Showa SFF-BP USD fork, adjustable for compression, rebound, and spring preload, 4.7 in. travel
Rear Suspension	Uni-Trak w/ Showa gas-charged shock, adjustable for compression, rebound, and spring preload, 5.3 in. travel
Front Brake	Brembo 4-piston Monoblock calipers, dual semi-floating 320mm discs w/ Kawasaki Intelligent ABS (KIBS)
Rear Brake	2-piston caliper, 260mm disc w/ Kawasaki Intelligent ABS (KIBS)
Tires, Front/Rear	Pirelli Diablo Rosso III; 120/70-17 / 190/55-17
Rake/Trail	24.9°/4.1 in.
Wheelbase	57.3 in.
Seat Height	32.7 in.
Fuel Capacity	5.0 gal.
Claimed Wet Weight	527 lb.
Contact	kawasaki.com