2008 Kawasaki Jet Ski Ultra 250X
The 250 horsepower pinnacle of PWC performance
Kawasaki extended its high-performance domination into the realm of personal watercraft with the 250 horsepower JET SKI Ultra 250X. The quickest and most powerful production PWC in history, Kawasaki’s supercharged Ultra 250X tears across the water at an electrifying pace that will invigorate even the most jaded of speed enthusiasts. Once up to speed, its precise handling and superb stability are equally impressive, thanks to a hull specifically designed to capitalize on the engine’s awesome performance.
The JET SKI Ultra 250X’s engine, jet drive and hull incorporate racing technology refined through Kawasaki’s multiple IJSBA championships. This knowledge application allows it to deliver the awesome acceleration of a drag racer, and help ensure excellent hook-up –even in rough water.
With a 1,498cc engine derived from Kawasaki’s capable JET SKI STX-15F watercraft as the foundation, the Ultra 250X produces power comparable to a normally aspirated high-performance three-liter engine. It accomplishes this amazing feat via the addition of a Roots-type supercharger. Unlike centrifugal superchargers or turbochargers, the Ultra 250X’s high-volume direct-drive supercharger delivers boost virtually instantly at any engine speed from idle to redline. This produces a linear, smooth torque curve that is ideal for a personal watercraft that needs to accelerate hard all the way from a standstill to its breath-taking top-end speed.
Heat build-up from compressing the intake air is a common drawback of forced-induction. The Ultra 250X uses of a large-capacity intercooler to overcome this handicap. With the 250X’s supercharger compressing the air to a maximum boost pressure of 11.4psi, the intake charge can reach extremely-high temperatures potentially limiting the engine’s power output. However, the 250X’s large-capacity intercooler brings the pressurized air down to ambient temperature or even less –ideal for producing maximum power.
A huge 155mm jet pump featuring the largest PWC impeller and nozzle Kawasaki has ever produced transfers the big power from supercharged 1,498cc engine into the JET SKI Ultra 250X’s blazing acceleration. Developed based on lessons learned from Kawasaki’s race machines, this pump was designed to deliver predictable thrust and good “traction,” even in rough water.
A significant factor in this extra “traction” are the pump’s eight guide vanes that smooth the flow of water from the impeller for efficient and powerful propulsion. The pump also incorporates a groove from the center to the rear of the ride plate which makes it easier to hold a stable heading for straight line riding. Complimenting the 155mm jet pump is an equally large, sophisticated three-blade impeller that delivers high performance with smooth and quiet operation.
In addition to more power and acceleration than any other production watercraft on the planet, the Ultra 250X also boasts a race-developed hull. Its hull design is just as comfortable in rough conditions as in calm. Even at high speeds, rough water can do little to deter the Ultra 250X. This combination of unearthly power mated with the latest hull technology permits Kawasaki’s flagship to literally cleave through waves that would send lesser machines ricocheting to a safe harbor.
Thanks to a specifically engineered hull, the Ultra 250X has the precise handling and superb stability to match its acceleration and top-speed capabilities. A fiberglass reinforced plastic (FRP) hull, it is loaded with DNA from Kawasaki’s IJSBA championship winning machines. This includes carefully designed sponsons and chins for enhanced straight-line stability and precise cornering, combined with a 22.5° deep-V hull that leans into corners like a motorcycle. This provides a smoother ride in rough water, helps passengers keep the rider in control during peak cornering g-forces.
The Ultra 250X features a five-step adjustable handlebar position that allows either stand-up or sit-down riding for a wide range of riders to enjoy superior comfort and versatility. As Kawasaki’s flagship watercraft, the 250X includes thoughtful standard features like an enormous 53-gallon of storage space including a detachable front storage compartment and a 20.6-gallon fuel tank for substantial cruising range.
From horsepower to handling and everything in between, once the spray settles after the first ride, one thing will be certain. This powerful “ultra” JET SKI model delivers a level of performance and excitement that is unmatched by any other watercraft.
||Jet Ski® Ultra® 250X
||4-stroke, 4-cylinder in-line, DOHC, 4-valve per cylinder, supercharged and intercooled, inducted water
|BORE X STROKE
||83 x 69.2 mm
||TCBI with digital advance
||3-blade, oval-edge stainless steel
||155 mm jet pump, axial-flow, single stage
||Semi-dry sump system
||250 hp @ 7,750 rpm