Compare Specs Discover '24 PWCs Browse Reviews
1987-1991 Kawasaki 300SX Review and Specs [Video]

1987-1991 Kawasaki 300SX Review and Specs [Video]

The Kawasaki 300SX was the successor of the proven JS300. They shared the same base 30 HP, single-cylinder engine but the 300SX featured a reed valve configuraton and was built on a smaller, more modern platform. This lively stand-up was introduced in 1987 and remained in production through 1991.

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

We at JetDrift have compiled all you need to know into this Kawasaki 300SX review!

1987-1991 Kawasaki 300SX Review

Kawasaki 300SX Hull and Top Deck

Unlike its outdated predecessors, the 300SX was built on an entirely new hull and top deck.

This fiberglass-reinforced Sheet Molding Compound (SMC) platform measured 78.74 inches in length, 26.4 inches in width, and 27.8 inches in height. In contrast, the original JS hull was 84.3 inches long and 24.4 inches wide.

Thanks to its shorter body and slightly lighter weight, the 300SX was more lively and maneuverable. On the other hand, it offered less stability and predictability.

Due to its small dimensions, this ski was often referred to as “The pit bike of the water.”Its redesigned top deck was also sleeker and more appealing than the bulky deck of the outdated JS hull.

Kawasaki 300SX Engine and Propulsion

The 300SX borrowed its engine from the JS300. This power mill was a purpose-built 2-stroke, 294cc, crankcase reed valve, vertical single Kawasaki marine engine rated at 30 HP.

The key features of this engine were as follows:

  • 2-stroke, single-cylinder, piston port valve configuration
  • Single Mikuni BN38 diaphragm type carburetor
  • NGK BR7ES spark plug
  • Magneto CDI ignition system
  • Open-loop cooling system
  • Electric starter
  • Oil injection system
  • Water-jacketed exhaust system
The propulsion system of the 300SX consisted of an industry-standard axial-flow, single-stage jet pump, featuring a 3-blade aluminum impeller, and a 6-vane stator.

This propulsion system delivered a maximum thrust of 276 pounds and a top speed of 33 mph.

The fuel consumption of the 300SX was 3.2 GPH at full throttle, so its larger 5-gallon fuel tank offered a cruising range of 52 miles or 1.6 hours.

Kawasaki 300SX Features

The 300SX came standard with some advanced features, including:

  • Handlebar-mounted start/stop button
  • Engine oil level gauge
  • Thumb throttle
  • Throttle limiter
  • Continuous self-activating bilge pump
  • 5-gallon fuel tank
  • Chone knob
  • Fuel valve knob
  • Storage compartment
  • Fire extinguisher compartment
  • Tool kit
  • Deck mats on the tray and the rails
  • Chin pad
The 300SX was introduced with a lot of innovative features. Its top deck housed a larger, 5-gallon fuel tank, which was 1.5 gallons bigger than its predecessor.

The well-designed top deck lacked an outdated control panel. Instead, the choke knob and the fuel valve knob were planted into both sides of the top deck.

The fuel tank cap and the oil tank cap were mounted into the bow and the latter was equipped with a level gauge.

Just like the tray, the sides of the rails were also covered with deck mats for a better grip and improved comfort.

The rear sides of the rails housed two storage compartments, one for the fire extinguisher and one for the tool kit and smaller sized gear.

Although the 300SX was equipped with advanced handlebar-mounted start/stop buttons. It still utilized an ATV-like thumb throttle lever on the left handlebar.

This was less convenient and offered less precise control than today’s finger throttle levers.

Although the 300SX had many innovative features, it still lacked a safety lanyard. This means that the engine didn’t stop automatically when you fell into the water. Instead, the machine started to go in slowly in circles and you would have to catch it to reboard!

Kawasaki 300SX Specs Chart

For your convenience, we’ve compiled the key specs of the 1989 Kawasaki 300SX into these charts:

Kawasaki 300SX Engine Specs

Kawasaki 300SXEngine Specs
Engine type2-stroke, vertical single, crankcase reed valve, water-cooled
Displacement294 mL (17.9 cu in.)
Bore and stroke76.0 x 64.9 mm (2.99 x 2.55 in.)
Compression ratio7.2 : 1
Ignition systemMagneto CDI
Lubrication systemOil injection (break-in period: oil injection and gas/oil mixture 50:1)
CarburetorMikuni BN34 diaphragm type (28 mm venturi)
Starting systemElectric
Battery12 V 19 Ah

Kawasaki 300SX Tuning Specifications

Kawasaki 300SXTuning Specifications
Spark Plug TypeNGK BR7ES
Spark Plug Gap0.7 ∼ 0.8 mm (0.028 ∼ 0.032 in.)
Ignition Timing16° BTDC @ 6 000 r/min (rpm) - 1.99 mm (0.078 in) @ 6 000 r/min (rpm)
Carburetor Idle Speed - in water1 700 ±100 r/min (rpm)
Carburetor Idle Speed - out of water2 200 ±100 r/min (rpm)
Compression Pressure1200 kPa (12.0 kg/cm2) (171 psi) - open throttle

Kawasaki 300SX Drive System

Kawasaki 300SXDrive System
CouplingDirect drive from engine
Jet Pump TypeAxial flow, single stage
Jet Pump Thrust125 kg (276 lb)
SteeringSteerable nozzle
BrakingWater drag

Kawasaki 300SX Performance

Kawasaki 300SXPerformance
Maximum Speed53 km/h (33 mph)
Minimum Turning Radius2.7 m (8.85 ft)
Draft (stationary)210 mm (8.27 in)
Fuel Consumption12 L/h (3.2 US gal/h) @full throttle
Cruising Range (1)57 km (36 mi) @full throttle
Cruising Range (2)1.6 hrs

Kawasaki 300SX Dimensions

Kawasaki 300SXDimensions
Overall length78.74 in (2 000 mm)
Overall width26.4 in (670 mm)
Overall height27.8 in (705 mm)
Dry Weight100 kg (221 lbs)
Fuel tank capacity5.0 US gal (19 L) including 1.2 (4.5 L)

Kawasaki 300SX Oil Specifications

Kawasaki 300SXOil Specifications
Engine Oil Type2-stroke, NMMA Certified for Service TC-WII
Engine Oil Tank Capacity2.2 L (2.3 qt (US)
Starter Gear Housing Oil - GradeSE or SF class
Starter Gear Housing Oil - ViscositySAE10W40, 10W50, 20W40, or 20W50
Starter Gear Housing Oil - Capacity0.2 L (0.21 US qt)
These charts are for informational purposes only! For exact specifications, please refer to the factory manual.


As a takeaway, we’ve answered the most common questions about the Kawasaki 300SX (1991 model)!

What is a Kawasaki 300SX?

The Kawasaki 300SX was a 2-stroke, single-cylinder Jet Ski manufactured by Kawasaki.

When did the Kawasaki 300SX Come Out?

The Kawasaki 300SX debuted in 1987.

What Years Did Kawasaki Make the 300SX?

Kawasaki marketed the 300SX from 1987 through 1991.

What Size was a Kawasaki 300SX?

The Kawasaki 300SX measured 78.74 inches in length, 26.4 inches in width, and 27.8 inches in height.

How Much Did a Kawasaki 300SX Weigh?

The dry weight of the Kawasaki 300SX was only 221 pounds.

How Many People Could Ride on a Kawasaki 300SX?

The Kawasaki 300SX could carry only one rider.

What Kind of Engine was in the Kawasaki 300SX?

The Kawasaki 300SX was powered by a 2-stroke, 294cc, single-cylinder Kawasaki marine engine.

Was the Kawasaki 300SX Supercharged?

The Kawasaki 300SX was powered by a naturally-aspirated engine.

Was the Kawasaki 300SX a 2-stroke?

Yes, the Kawasaki 300SX was powered by a 2-stroke engine.

How Much Horsepower Did a Kawasaki 300SX Have?

The Kawasaki 300SX produced 30 HP out of the box.

How Much Oil Did a Kawasaki 300SX Hold?

The Kawasaki 300SX was designed with an oil system featuring a 2.3-quart oil tank.

How Much Fuel Did a Kawasaki 300SX Hold?

The Kawasaki 300SX was equipped with a 5-gallon fuel tank.

How Much Fuel Did a Kawasaki 300SX Use?

The claimed fuel consumption of the Kawasaki 300SX was about 3.2 GPH at full throttle.

What was the Fuel Range of the Kawasaki 300SX?

The fuel range of the Kawasaki 300SX was about 52 miles or 1.6 hours at full throttle.

How Fast Did a Kawasaki 300SX Go?

The top speed of a Kawasaki 300SX was about 33 mph under ideal conditions.

Did the Kawasaki 300SX Have a Reverse?           

No, the Kawasaki 300SX didn’t have a reverse system.

Did the Kawasaki 300SX Have a Brake?

No, the Kawasaki 300SX was manufactured without a brake system.

How Much Does a Kawasaki 300SX Cost?

The asking price of a used Kawasaki 300SX varies between $1,000 and $3,000 depending on the year and its condition.