2011 Kawasaki Jet Ski Ultra 300X First Ride

March 12, 2011
Adam Waheed
By Adam Waheed
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His insatiable thirst for life is only surpassed by his monthly fuel bill. Whether rocketing on land, flying through the air, or jumping the seas, our Road Test Editor does it all and has the scars to prove it.

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Watch the 2011 Kawasaki Jet Ski Ultra 300X First Ride Video review and see what it’s like to pilot a 300 horsepower personal watercraft.

“Have you ever seen a sad person on a WaveRunner?” That’s what comedian Daniel Tosh joked during one of his hilarious stand-up comedy routines. And while funny, it’s also true. So when it comes to smiling and having fun on the water this summer you’ll be hard pressed to find a more entertaining way to splash around the waves than at the controls of the 2011 Kawasaki Jet Ski Ultra 300X. From bow-to-stern, Kawasaki’s flagship personal watercraft has been redesigned to make it not only the most powerful production PWC but one that is easy to own and operate.


The new 300X is a direct replacement for the Jet Ski Ultra 260X from which it’s based. It continues to utilize a water-cooled and fuel-injected 1498cc Inline-Four derived from Team Green’s Ninja line of high-performance sportbikes. The engine has some important tweaks designed to increase operating efficiency as well as making it more durable against the extra 40 horsepower load courtesy of the updated intake system (more on that later).

Reshaped pistons are lighter and reduce mechanical losses (8.4:1 compression ratio is unchanged) and the eight exhaust valves feature a reinforced head stem that is 19% wider than before. The camshafts have added lubrication orifices and the valve timing was modified for increased top-end engine performance. A stronger cam chain was also fitted. The engine’s bottom-end also received attention in the form of a stronger crankshaft and the engine cases are stouter too. The exhaust also received some improvements to reduce sound and the chance of water entering during extended idling thru a no wake zone.

The 11 Kawasaki Jet Ski Ultra 300X is surprisingly agile for a 1000-plus pound boat.
The 11 Kawasaki Ultra Jet Ski 300X is powered by a water-cooled and fuel-injected 1498cc supercharged Inline-Four four-stroke engine.
Electronic trim allows the rider to alter the skis angle of attack based on water conditions or personal preference.
The handlebars feature a five-way adjustable tilt. We preferred the highest setting for both stand-up and sit down riding.
Updated instrumentation is easy-to-read at a glance.
(Top) The ’11 Kawasaki Jet Ski Ultra 300X is surprisingly agile for a 1000-plus pound boat. (Bottom) Updated instrumentation is easy-to-read at a glance.

The biggest news however is the redesigned induction system highlighted by Eaton’s latest and greatest Twin Vortices Series (TVS) supercharger. This is the same supercharger that’s used in the 638 horsepower Corvette ZR1 and 556 horsepower Cadillac CTS-V sports cars. It delivers 6.3 psi more boost than before (17.3 max) which nets a total of 300 horsepower at just 7750 rpm (measured at the crankshaft). That’s over 200 horsepower per liter—a figure almost unheard of in the motorsports industry. A 20.6 gallon capacity fuel tank feeds the engine.

Extra power equates to more engine heat so engineers fitted a water-to-air intercooler to reduce the temperature of the intake air consumed by the engine. Additionally the 300X features three independent cooling lines. The first line cools the supercharger and engine while the second line cools the stator before providing auxiliary cooling to the engine and exhaust manifold. The third line pumps cool water through the intercooler.

The electronics also received some updates in the form of an updated engine management system. It is highlighted by a new electronic throttle valve that allows for improved throttle trigger response. Other functionality includes adjustable cruise control and the ability to limit speed to five mph when piloting through a No Wake zone. Both of these features can be accessed via buttons on the right-hand size of the handlebar.

Lastly, the 300X offers an economy engine setting (activated by a button on the left handlebar) which alters the fuel map allowing for a claimed 15% improvement in fuel economy at just below 38 mph. An “ECO” icon on the right side of the LCD display lets the rider know when it’s engaged. Furthermore a triangular “eco” icon appears on the left-side of the LCD when traveling at the most efficient speed regardless of whether you’ve selected ECO mode. While the chances of any of the electronics failing is miniscule, fail-safe redundancy was built-in so if something were to fail the Jet Ski can still make it back to shore.

Drivetrain refinements include a reshaped three-blade impeller with a larger surface area that pushes more water. It is fed from a 6.2-inch diameter jet pump and updated eight-vane intake grate with staggered horizontal vanes (from two to four) that allow the pump to inhale more water. Additionally, the shape of the grate scoops up water more effectively and also keeps the front of the ski from rising out of the water during acceleration. This allows the 300X to deliver an astounding 1769 pounds of thrust (up from 1585). Lastly an electronic trim system allows the rider to alter the attitude of the output nozzle in an eight-degree range (up or down) to compensate for rough water or personal riding preference.

The profile and thickness of the fiberglass reinforced plastic hull also got some attention. The inner portion of the bow was reinforced to compensate for the higher loads placed due to the increase in engine power. The angle of the bow continues to be sharp so it slices through choppy water more effectively and it features a four-ridge design that reduces water spray in the cockpit. A number of strategically placed chines and sponsons (similar to tiny rudders) provide stability and allow the ski to hold a line while turning. Curb weight has also been reduced by 43 pounds due in part to the lighter yet stronger hull design.

Visually the Ultra 300X sports a more futuristic look. The front profile of the ski has been tweaked for better aerodynamics and the nose is lower and the front hatch is now wider than before. Dual air intakes are placed on each side and the windscreen is new too. It comes in two colorways: Ebony / Lime Green and Ebony / Sunbeam Red and retails for $14,499 with a 12-month warranty. Extended warranty options are available from Kawasaki’s Good Times Protection Plan.


To discover how Kawi’s new ski performs we were lucky enough to be able to ride it in the turquoise blue water of the island of Bimini in The Bahamas. Yeah we know, rough job but somebody’s got to…

If you’re not boarding the Jet Ski from the dock getting aboard is still simple thanks to the retractable rear boarding step and large grab handle which makes it easy to hoist yourself on deck. Hop into the seat and there is a considerable amount of room for a person of above average height. Kawasaki claims the seat is a little over 0.5 inches narrower than the Ultra 260X but we couldn’t tell a difference.

The seat itself is long and designed to accommodate up to three people. It has a firm feel to it and the cover is tacky enough for you to remain in place but not too tacky as to not allow you to move around. Grippy material lines the foot well providing traction and aiding in overall control. The handlebars are wide and provide a fair amount of leverage so you don’t need to be a body builder when steering. Another excellent feature is the five-way adjustable tilt steering. We preferred the high setting which worked well whether we were riding in the standing or seated position. Instrumentation is easy-to-read at a glance.

Steering effort is minimal and the 300X will surprise you with its agility.
The 300X is virtually unsinkable and features an automatic bilge system to purge water from the inside of the hull during submarine maneuvers.
One of the best things about riding Jet Skis is that it usually doesnt hurt when you crash.
The 300Xs hull holds a line well when cornering  never turning more or less than what the rider inputs into the handlebar.
Splashing in the water aboard the 11 Kawasaki Ultra Jet Ski 300X.
One of the best features of the 300X is the ability to take two passengers along for the ride.
(Above) Steering effort is minimal and the 300X will surprise you with its agility. (Below) One of the best features of the 300X is the ability to take two passengers along for the ride.

In terms of storage the 300X offers a humongous storage compartment located beneath the main front cowl. It is easily accessed via a plastic latch and can accommodate a fair amount of cargo for an all-day adventure.

Getting off and running is as simple as inserting one of two plastic keys into the small storage compartment between the rider’s legs. The orange key is designed for experienced pilot’s and provides full engine power. The yellow “SLO” key reduces engine power considerably so it doesn’t intimidate a new rider. There is also a handy reverse lever which allows you to back out of position. Attach the red plastic tether to the handgrip, press the starter button and you’re off and running. It is worth mentioning that the 300X generates so much thrust at idle that it’s important to make sure that there are no objects in front or behind you when you fire up the engine to avoid damage to the hull.

Idling out through No Wake zones is always tedious but the handy one-touch wake zone button makes things easy by automatically modulating your speed (five mph) until you get out into open water.

Pull the throttle trigger and it’s almost unfathomable how hard this Jet Ski lunges forward. Seriously, I’ve ridden my fair share of high-performance skis, but this one takes the cake—it’s the closest thing to riding a Ninja ZX-10R sportbike on the water.

It is borderline absurd how much thrust the ski pumps out at all throttle settings and it doesn’t make a difference whether you’re cruising along at 40 mph or at 10 mph when you hit the gas; either way it shoots you forward in the same voracity as some stomach churning amusement park rides. Both engine throttle response and traction from the jet pump is instantaneous. Thank God top speed is electronically limited to 67 mph.

In addition to a firm handlebar grasp, one technique that helps you stay in control during full throttle acceleration is to squeeze your knees into the seat while standing in a crouched position. Beside the whine of the supercharger engine noise is fairly subdued.

Turn the handlebars and the 300X is surprisingly agile for a 1000-plus pound boat. As opposed to land based vehicles the throttle has to be depressed in order for maintain steering control. However the 300X has logic built into it so that it will automatically continue to feed in some throttle if you turn the handlebars and forget to feed in the throttle. The system is calibrated perfectly and can be a real life saver in say a panic situation.

Once turning the ski hold’s a line well and doesn’t turn more or less than what the rider inputs into the handlebar. We also really appreciated the electronic trim which allows the rider to alter the ski’s angle of attack based on whether the water surface is smooth or choppy. For rough water we preferred to have the trim all the way up which allowed the nose to cut through waves better. Conversely in smooth water we tilted the jet all the way down so it puts more weight on the back of the boat thus allowing it to carve harder turns.

Straight-line stability was excellent on smooth water and it was very easy to reach and maintain top speed. On rough water it proved more difficult to maintain high speeds but the ski tracked well though chop resisting the urge to swap from side-to-side.

Leave it to Team Green to continue to raise the bar in performance expectations from a personal watercraft. Not only is the 300X an absolute straight-line rocket, with its advanced electronics and sharp yet stable handling behavior it is an amazingly friendly ski to operate and is guaranteed to keep a slap happy smile on your face—just remember to let off the throttle.