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2003-2007 Kawasaki STX-12F Review and Specs [Video]

2003-2007 Kawasaki STX-12F Review and Specs [Video]

The Kawasaki STX-12F was the flagship Kawasaki Jet Ski from 2003 through 2007. It was built on the stable and predictable STX platform and utilized a 1199cc, 125 HP engine option. The model was replaced by the more powerful STX-15F in 2008.

If you want to find out more about this ski, you’ve come to the right place.

We at JetDrift have compiled all you need to know into this Kawasaki STX-12F review!

2014-2022 Kawasaki STX-12F Review

Kawasaki STX-12F Hull and Top Deck

As reported by Kawasaki, the SXT-12F inherited its platform from the world championship-winning 1200STX-R.

This race-inspired hull was made of fiberglass reinforced plastic (FRP) and measured 122.8 inches in length, 46.5 inches in width, and 43.1 inches in height.

This shell was made in one solid piece for optimum rigidity. This means that the engine mounts, strengthening units, and stringers were laminated directly to the hull rather than gluing them in as separate assemblies.

The dry weight of the STX-12F was 736 pounds and it could carry 16.36 gallons of gas along with 23.5 gallons of gear. The storage units included a standard bow storage bin, a glovebox, and a rear storage case under the seat.

The latter housed a tool kit and a factory-installed fire extinguisher container but the extinguisher itself was not standard equipment.

Its top deck featured an outdated one-piece seat, which was heavier and less practical than today’s 2-piece PWC saddles. The seating capacity of the ski was three riders.

This platform was carried over to the STX-15F and later to the revamped STX-160 series.Therefore, it’s safe to say that Kawasaki’s STX hull has been in production since 2003 without any significant changes!

Kawasaki STX-12F Engine and Propulsion

The power source was the STX-12F, which was a 4-stroke, 1199cc, inline 4-cylinder engine rated at 125 HP. 

This engine was derived from the Ninja ZX-12R motorcycle and utilized a regular cable throttle and a mechanical reverse system.But it also had many innovative features including digital fuel injection, a semi-dry-sump lubrication system, open-loop cooling, and electric start.

Engine power was delivered to an axial-flow, single-stage jet pump housing an oval-edge, stainless steel, three-blade impeller.

This advanced propulsion system offered no less than 827 pounds of thrust. which translated to a top speed of 55 mph.

The fuel economy of the ski was 9.5 GPH at full throttle, which ensured a fuel range of 90.7 miles or 1 hour and 43 minutes of playtime.

What’s more, the STX-12F earned the “CARB three-star” emissions rating, which allowed it to ride on emissions-sensitive waters like Lake Tahoe.

Over the years, this engine underwent some important updates, since the early-year models were prone to damaging its pistons in hot weather or with low-octane fuel.

Riders agree that the most reliable STX-12Fs were manufactured in 2007 with the upgraded ECU.

Kawasaki STX-12F Features

The standard features of the Kawasaki STX-12F were as follows:

  • Multifunction dashboard
  • Kawasaki Smart Steering system (KSS)
  • Smart Learning Operation (SLO)
  • Mechanical reverse
  • 16.38-gallon fuel tank
  • Front storage compartment
  • Glovebox
  • Under-seat storage case
  • Tool kit (stored in the back of the rear seat)
  • Fire extinguisher container
  • One-piece seat for 3 riders
  • Rear grab handle
  • Reboarding step
  • Mooring cleats
  • Tow hook
  • Sponsons
  • Deck mat
There is no question that the biggest flaw of the STX-12F was the lack of an electric brake and reverse system. Just like other jet skis in its time, this model was engineered with a mechanical reverse system.

Unfortunately, this design offered less comfort and safety than their more modern electric-controlled counterparts.

This unit wasn’t intended to be used as a brake, so you had to rely on the water drag when you wanted to slow down or stop the STX-12F.

Kawasaki STX-12F Performance Handling

The STX-15F was known as a reliable family jet ski, yet powerful enough for adrenaline junkies.

It was lighter than any competitor, so it could hit 55-57 mph even with its moderate, 125 HP engine.

Thanks to its race-intended hull design, the STX-12F was very agile and offered a sporty riding experience.

It stayed hooked on a mild chop and cut through it with ease, but it suffered on bigger waves due to its flat hull design.

Therefore, the STX 12-F wasn’t as stable and predictable as the successor Ultra Jet Skis with deep-V hulls.

Thanks to its roomy top deck and easy handling, the ski instantly became popular among families and beginners. It came standard with the Smart Learning Operation “SLO” mode, designed to restrict engine performance.

Novice riders also appreciated the innovative Kawasaki Smart Steering. What was this feature?

In a nutshell, the Kawasaki Smart Steering (KSS) was a safety feature that helped the steering in off-throttle situations. The system featured a steering sensor linked directly to the main computer (ECU). When you released the throttle at a higher speed but kept the handlebars turned, the computer activated the KSS, which raised the engine speed to provide some thrust for the turn.

This means that the KSS ensured some steering control if you dropped the throttle in emergencies.

After five years of production, the legendary STX-12F was replaced by the more powerful STX-15F in 2008.

Kawasaki STX-12F Specs Chart

For your convenience, we’ve compiled the key specs of the 2006 Kawasaki STX-12F into these charts:

Kawasaki STX-12F Engine Specs

Kawasaki STX-12FEngine Specs
Type4-stroke, 4-cylinder, water-cooled
Displacement1 199 cm³ (73.2 cu in.)
Bore x Stroke83 × 55.4 mm (3.27 × 2.18 in.)
Compression Ratio11.2 : 1
Ignition SystemDigital transistor
Lubrication SystemSemi-drysump
Fuel SystemDigital fuel injection
Starting SystemElectric starter
Battery12V, 18Ah

Kawasaki STX-12F Tuning Specifications

Kawasaki STX-12FTuning Specifications
Spark PlugNGK CR9EK
Spark Plug Gap0.7 - 0.8 mm (0.028 - 0.032 in.)
Spark Plug TerminalSolid post terminal
Ignition Timing6° ATDC @1 300 r/min (rpm) - 32° BTDC @3 000 r/min (rpm)
Idle Speed - in water1 300 ±100 r/min (rpm)
Idle Speed - out of water1 300 ±100 r/min (rpm)

Kawasaki STX-12F Drive System

Kawasaki STX-12FDrive System
CouplingDirect drive from engine
Jet Pump - TypeAxial flow, single stage
Jet Pump - Thrust3 675 N (375 kg) (827 lb)
SteeringSteerable nozzle
BrakingWater drag

Kawasaki STX-12F Performance

Kawasaki STX-12FPerformance
Minimum Turning Radius4.0 m (13.1 ft)
Fuel Consumption36 L/h at full throttle (9.5 US gal/hr)
Cruising Range146 km at full throttle (90.7 mi - 1 hr and 43 min)

Kawasaki STX-12F Dimensions and Capacities

Kawasaki STX-12FDimensions and Capacities
Maximum number of riders3 persons (1 operator and 2 passengers)
Load Limit225 kg including riders and cargo (496 lb)
Overall Length3 120 mm (122.8 in.)
Overall Width1 180 mm (46.5 in.)
Overall Height1 050 mm (41.3 in.)
Dry Weight334 kg (736 lb)
Fuel Tank Capacity62 L (16.38 US gal)

Kawasaki STX-12F Engine Oil

Kawasaki STX-12FEngine Oil
Engine Oil TypeAPI SF, SG, SH or SJ with JASO MA
Engine Oil ViscositySAE10W-40
Engine Oil Capacity5.0 L (5.3 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 STX-12F!

What is a Kawasaki STX-12F?

The STX-12F was a race-ready sit-down jet ski manufactured by Kawasaki.

When did the STX-12F Come Out?

The Kawasaki STX-12F was released in early 2003.

What Years Did Kawasaki Make the STX-12F?

Kawasaki marketed the STX-12F from 2003 through 2007.

What Size was a Kawasaki STX-12F?

The Kawasaki STX-12F measured 122.8 inches in length, 46.5 inches in width, and 41.3 inches in height, while its maximum draft was 14.6 inches.

How Much Did a Kawasaki STX-12F Weigh?

The dry weight of the Kawasaki STX-12F was 736 pounds.

What Size Storage Compartment Did the STX-12F Have?

The total storage capacity of the STX-12F was 23.5 gallons, split into a front storage, a glovebox, and a storage case under the rear seat.

How Many People Could Ride on a Kawasaki STX-12F?

The Kawasaki STX-12F could carry 3 adult riders.

What Kind of Engine was in the Kawasaki STX-12F?

The Kawasaki STX-12F was powered by a 4-stroke, 1199cc, fuel-injected, 4-cylinder Kawasaki engine.

Was the Kawasaki STX-12F Supercharged?

The Kawasaki STX-12F was powered by a naturally-aspirated engine.

Was the Kawasaki STX-12F a 4-stroke?

Yes, the Kawasaki STX-12F was powered by a 4-stroke engine.

How Much Horsepower Did a Kawasaki STX-12F Have?

The Kawasaki STX-12F produced a remarkable 125 HP.

What Kind of Oil Did a Kawasaki STX-12F Use?

According to the owner’s manual, the Kawasaki STX-12F used SAE10W-40 engine oil (API SF or SG, SH or SJ, with JASO MA).

How Much Oil Did a Kawasaki STX-12F Hold?

The oil capacity of the Kawasaki STX-12F was 5.3 US quarts (5.0 L).

How Much Fuel Did a Kawasaki STX-12F Hold?

The Kawasaki STX-12F was equipped with a 16.38-gallon fuel tank.

How Much Fuel Did a Kawasaki STX-12F Use?

The fuel consumption of the Kawasaki STX-12F was about 9.5 GPH at WOT.

What was the Fuel Range of the Kawasaki STX-12F?

The claimed fuel range of the STX-12F was about 90.7 miles at full throttle, which equals 1 hour and 43 minutes of riding time.

How Fast Did a Kawasaki STX-12F Go?

The top speed of a Kawasaki STX-12F was 55-57 mph under ideal conditions.

Did the Kawasaki STX-12F Have a Reverse?       

Yes, the Kawasaki STX-12F came with a mechanical reverse.

Did the Kawasaki STX-12F Have a Brake?           

No, the Kawasaki STX-12F was manufactured without a brake system.

Did the Kawasaki STX-12F Have Speakers?

The Kawasaki STX-12F was marketed without speakers.

Could the Kawasaki STX-12F Tow a Skier or a Wakeboarder?

Yes, the Kawasaki STX-12F could tow a wakeboarder or skier with ease.

How Much Does a Kawasaki STX-12F Cost?

The asking price of used Kawasaki STX-12Fs varies between $3,000 and $8,000 depending on the year and its condition.