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1990-1995 Kawasaki 550SX Review and Specs [Video]

1990-1995 Kawasaki 550SX Review and Specs [Video]

The Kawasaki 550SX was a more advanced configuration of the proven Kawasaki JS550. It packed many innovative features including an all-new mixed-flow jet pump, automatic rev limiter, side rail pads, and handlebar-mounted start/stop buttons.

If you want to find out more about this legendary jet ski, this post is for you.

We at JetDrift have compiled all you need to know into this Kawasaki 550SX review!

1990-1995 Kawasaki 550SX Review

Despite the “SX” suffix in its name, the Kawasaki 550SX was still built on the original JS hull, inherited from the proven JS400/440/550 series.

That’s why this model was often referred as the JS550SX.

This platform measured 84.3 inches in length, 24.4 inches in width, and 25.5 inches in height. The dry weight of the 550SX was only 251.3 pounds, which ensured easy handling and launching.

In contrast, the more advanced Kawasaki “SX” Jet Skis in those years (like the 300SX and the 650SX) featured new hulls and more modern, rounded top decks.

Compared to these innovative skis, the old-school 550SX seemed fairly outdated, yet it was still popular among riders.

So it was no surprise that this model remained in production through 1995.

The power source of the 550SX was the proven 2-stroke, 530cc, vertical twin Kawasaki marine engine.

This power mill was inherited from the JS550, but was redesigned for a higher performance.

The 1990 550SX still featured a piston port configuration, which was replaced by a reed valve engine configuration for 1991. The new engine also got an upgraded drive shaft, aluminum cylinders, and an advanced underwater exhaust outlet.

The latter was a great invention since its predecessors featured an odd front deck exhaust outlet, which proved to be quite noisy.

Another innovative feature of the 550SX was its automatic rev limiter (a.k.a. automatic RPM control). As the name suggests, it was intended to prevent the engine from over-revving when the impeller was out of the water.

This saved riders a lot of headaches since over-revving was a common issue on earlier models.

Thanks to these performance upgrades, the engine power of the 530cc Kawasaki twin jumped from 41 to 47 HP.

Besides these engine and exhaust upgrades, another performance-enhancing feature of the 550SX was its all-new, high-capacity, mixed-flow jet pump.

For the most comfort and best grip, the ski was equipped with a thick rubber tray and side rail pads.

Regarding riding experience: the 550SX was super agile and offered excellent maneuverability. Its slim nimble hull made it fun to ride but it was challenging for beginners.

Riding this ski well required a lot of practice, a good sense of balance, and great athletic skills.

The 550SX offered a great throttle response and topped out at 37-39 mph on good days.

Its hull was prone to porpoising, which could be reduced by installing a longer aftermarket ride plate, which also improved stability at higher speeds.

Unfortunately, the ski lacked an oil injection system, so it had to be fueled by a gas/oil premix.

The standard features of the 550SX were as follows:

  • Automatic rev limiter
  • Underwater exhaust outlet
  • Handlebar-mounted start/stop buttons
  • Starter interlock switch
  • Throttle limiter
  • Thumb throttle
  • Automatic bilge system
  • 3.4-gallon fuel tank
  • Floatation cells
  • Fire extinguisher compartment
  • Tool kit
  • Fully padded riding tray
  • Side rail pads
  • Bumper rails
  • Chin pad
  • Self-circling rider pick up
Surprisingly, the 550SX lacked some key features tht come standard on today’s jet skis.

Instead of a convenient finger throttle, it featured an ATV-like thumb throttle lever.

It also lacked a shut-off switch and a safety lanyard, so the engine didn’t stop automatically when you fell into the water.

Instead, it had a self-circling system that forced the machine to idle in circles around you after a fall. This meant that you had to catch the ski circling in the water to reboard.

As you can imagine, this was very unsafe and uncomfortable!

This is why modern jet skis come with a shut-off valve that stops the engine in case of a fall.

Kawasaki marketed the deservedly-popular 550SX from 1990 through 1995 when it was phased out and replaced by the more powerful 750SX.

Kawasaki 550SX Timeline

Let’s drill into the details and talk about the key features of these jet skis in their various model years!

1990 Kawasaki 550SX

The 1990 Kawasaki 550SX was a close relative of the ’89 JS550. They shared the same hull and engine, but the 550SX came with some more advanced features, including:

  • Redesigned siphon bilge
  • The impeller pitch increased from 16” to 17.5”
  • Thinner, fine spline driveshaft
  • Single, sealed bulkhead bearing
  • Different bulkhead bolt pattern
  • Plastic coupler cover
  • Removable, thick rubber tray pads
  • Redesigned tray to fit the new pads
  • Covered control panel door
  • The fire extinguisher compartment was moved to the left side
  • Front and rear plastic bumpers
  • 1″ longer ride plate
  • Smaller pump shaft and smaller, sealed pump bearings
  • The cone in the pump lacked zerk fitting
  • Straighter handlebars
  • Blue/pink graphics
Just like the ’89 JS550, the 550SX was manufactured with the piston-port 530cc Kawasaki engine, featuring single piston rings, Mikuni BN44 carbs, and a fuel flood-type rev limiter.

Hence, the engine power of the ’90 550SX was 41 HP at 6250 RPM while its pump delivered a maximum thrust of 368 pounds.

1991-1995 Kawasaki 550SX

Changes and upgrades over the ’90 550SX model include:

  • The engine was upgraded to reed valve style (formerly: piston port)
  • Increased cylinder stud spacing
  • Dual ring pistons (formerly: single thick piston ring)
  • Keihin CDKII 38mm carb (formerly: Mikuni BN44)
  • CDI-integrated electronic rev limiter (formerly: fuel flood type)
  • Engine color was changed to silver (formerly: black)
  • Larger steering bushings
  • Quicker turn ratio
  • Siphon bilge system mounted directly to the hull
Thanks to these features, the engine power of the ’91 Kawasaki 550SX jumped from 41 up to 47 HP, which translated to an increase in top speed of 2 mph.

This heavily redesigned model was carried over to the models from ’92-’95 without any significant changes. The only distinguishing feature of the various model years was the decals:

  • 1991-1992: Blue/pink “lightning” graphics
  • 1993-1995: Purple/pink “fragmented” graphics
The base color of each model was a uniformly white Gelcoat on both the hull and top deck.

1998 Kawasaki 550SX

It’s a lesser-known fact that the 550SX made a comeback in 1998.

Labeled as Kawasaki 550SX Commemorative, the ski featured a white hull and top deck, and completed with large Jet Ski and 550SX decals.

Aside from these, it was completely identical to the models from ’91-’95.

Only 300 of these commemorative-edition 550SXs were manufactured, which were exclusively available in Japan.

Kawasaki 550SX Specs Charts

For your convenience, we’ve compiled the key specs of the 1994 Kawasaki 550SX into these charts:

Kawasaki 550SX Engine Specs

Kawasaki 550SXEngine Specs
Engine type2-stroke, vertical twin, piston reed valve, water-cooled
Displacement530 mL (32.3 cu in)
Bore and stroke75 x 60 mm (2.95 x 2.36 in)
Compression ratio7.2 : 1
Ignition systemMagneto CDI
Fuel / LubricationGas/ Oil Premix ratio 50:1
CarburetorKeihin CDK 38-32
Starting systemElectric starter
Battery12 V 19 Ah

Kawasaki 550SX Tuning Specifications

Kawasaki 550SXTuning Specifications
Spark Plug TypeNGK BR8ES
Spark Plug Gap0.7 ∼ 0.8 mm (0.028 ∼ 0.032 in.)
Ignition Timing21° BTDC @6 000 r/min (rpm) - 2.52 mm(0.1 in) @6 000 r/min (rpm)
Carburetor Idle Speed - in water1 500 ±100 r/min (rpm)
Carburetor Idle Speed - out of water1 900 ±100 r/min (rpm)
Compression Pressure1 320 kPa (13.5 kg/cm2) 192 psi

Kawasaki 550SX Drive System

Kawasaki 550SXDrive System
CouplingDirect drive from engine
Pump typeMixed flow, single stage
Pump thrust167 kg (368.2 lb)
SteeringSteerable nozzle
BrakingWater drag

Kawasaki 550SX Performance

Kawasaki 550SXPerformance
Minimum Turning Radius2.75 m (9.0 ft)
Draft (Stationary)200 mm (8.0 in)
Fuel Consumption17 L/hr (4.5 US gal/hr) @full throttle
Cruising Range (1)47 km (29.2 mi) @full throttle
Cruising Range (2)45 minutes

Kawasaki 550SX Dimensions

Kawasaki 550SXDimensions
Overall length84.3 in (2 140 mm)
Overall width24.4 in (620 mm)
Overall height25.2 in (640 mm)
Dry weight114 kg (251.3 lbs)
Fuel tank capacity13 L (3.4 US gal) including 3.4 L (0.9 US gal) reserve
These charts are for informational purposes only! For exact specifications, please refer to the factory manual.

Takeaways

As a takeaway, we’ve answered the most common questions about the Kawasaki 550SX!

What is a Kawasaki 550SX?

The Kawasaki 550SX was a high-performance stand-up Kawasaki Jet Ski.

When did the Kawasaki 550SX Come Out?

The Kawasaki 550SX debuted in 1990.

What Years Did Kawasaki Make the 550SX?

Kawasaki marketed the 550SX from 1990 through 1995.

What Size was a Kawasaki 550SX?

The Kawasaki 550SX measured 84.3 inches in length, 24.4 inches in width, and 25.2 inches in height, while its draft was 8 inches.

How Much Did a Kawasaki 550SX Weigh?

The dry weight of the Kawasaki 550SX was only 251.3 pounds.

How Many People Could Ride on a Kawasaki 550SX?

The Kawasaki 550SX could carry only one rider.

What Kind of Engine was in the Kawasaki 550SX?

The Kawasaki 550SX was powered by a 2-stroke, 530cc, vertical twin Kawasaki marine engine (1990: piston port/41 HP, 1991-1995: reed valve/47 HP).

Was the Kawasaki 550SX Supercharged?

The Kawasaki 550SX was powered by a naturally-aspirated engine.

Was the Kawasaki 550SX a 2-stroke?

Yes, the Kawasaki 550SX was powered by a 2-stroke engine.

How Much Horsepower Did a Kawasaki 550SX Have?

The Kawasaki 550SX produced 41 or 47 HP depending on the model year. (1990: 41 HP, 1991-1995: 47 HP)

How Much Oil Did a Kawasaki 550SX Hold?

The Kawasaki 550SX didn’t have an oil system as it ran on premix.

How Much Fuel Did a Kawasaki 550SX Hold?

The Kawasaki 550SX was equipped with a 3.4-gallon fuel tank.

How Much Fuel Did a Kawasaki 550SX Use?

The claimed fuel consumption of the Kawasaki 550SX was about 4.5 GPH at full throttle.

What was the Fuel Range of the Kawasaki 550SX?

The fuel range of the Kawasaki 550SX was about 29 miles or 45 mins)at full throttle.

How Fast Did a Kawasaki 550SX Go?

The claimed top speed of a Kawasaki 550SX was 37-39 mph under ideal conditions. (’90 550SX: 37 mph, ’91-’95 550SX: 39 mph)

Did the Kawasaki 550SX Have a Reverse?           

No, the Kawasaki 550SX didn’t have a reverse system.

Did the Kawasaki 550SX Have a Brake?

No, the Kawasaki 550SX was manufactured without a brake system.

How Much Does a Kawasaki 550SX Cost?

The asking price of a used Kawasaki 550SX varies between $1,000 and $8,000 depending on the year and its condition.