JS550sx

The JS550sx is a stand-up personal watercraft created by Kawasaki from 1990 to 1995 in response to the JS550's popularity. When it was first built, stand-up watercraft were dominating the market and in 92-93 Kawasaki offered 3 different stand-up models (550sx, 650 and 750). One of the biggest appeals of the 550 is its lighweight, the lighest standup ever produced. It brings cosmetic as well as functional updates to the same familiar hull as the JS300, JS400, JS440 and JS550.

A common complaint about the 550 is its handling. When compared to newer models, it is significantly harder to keep "hooked up" in tight corners. When exceeding speeds of about 45, the hull likes to "seek", which means it takes a lot of rider skill to keep it moving in a straight line. Despite this, the 550 is still a ver popular ski to this day, in part due to its wide availability.

Changes from previous models

Costmetically, the graphics kit was updated with pink and blue lightning higlights. The rider area also was refitted with rubber sides instead of the older turfed sides. The new rear exhaust, as opposed to the front tube exhaust, helps to keep the exhaust fumes out of the rider's face.

The mid 91 models also got an engine upgrade. The displacement is the same, but it now has reeds. This motor received a lot of praise from being easier to start, more reliable and generally better running than the older pistion port motors. All sx models also have a newer pump design which reduces maintenance mostly because of the sealed bulk-head bearing.

Here are the year differences:

1990(mid)-1991(mid)

* Motor:Black Piston Port 550
* Single ring piston
* Carb:single 28 mm Mikuni BN
* rear exit exhaust outlet
* thicker rubber side mats
* Maintenance free pump
* Thumb throttle
* JETPOWER exhaust
* Stainless pump inlet wear ring

1991(mid)-1995

* Motor:Silver Reed Valve 550 (Highly sought after, known for smooth throttle response)
* Dual ring piston
* Carb:single 38 mm keihin
* rear exit exhaust outlet
* thicker rubber side mats
* Maintenance free pump
* Thumb throttle
* JETPOWER exhaust
* Stainless pump inlet wear ring

External links

* [http://www.groupk.com/ Group K] – engine modifications
* [http://www.pwctoday.com/ pwctoday.com] – huge site of PWC enthusiasts