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Kawasaki JS440 / 550SX Build

Kawasaki JS440

Kawasaki JS440 / 550SX Build

By Jason Bull


So just for a little background of how I found my passion for the mighty Kawasaki JS440 JetSki. It all started when I visited a classmate, Denny Moran’s place in around 82-83. I believe his dad was a marine mechanic or something like that in Sydney. They had a jetty and sitting on the end was a black 650 with Darth Vader airbrushed on it. That was pretty damn cool to a kid in 82!

A couple years passed and I traveled up to the Gold Coast (Australia) for the Christmas holidays around 84 and from the hotel balcony I saw what I’m presuming was the Sea World JetSki team blasting around, going up the riverbank etc and from then on I was sold on skis for good!

Kawasaki JS440


In 1987 I finally got around to buying one of my own but spent all my time trying to get the darn thing to run. Haha, sound familiar? When I did get it to run I had a blast and was ripping it around Sydney Harbour but it was never really reliable enough so I ended up selling it. About this time snowboarding had started and this became my new passion for the next decade and I became one of Australia’s first group of sponsored riders.

A mate of mine happened to buy one of Gonzo’s (Southcoast Jet Skis) ex pro mod race 550’s and got to have a blast on that, was amazing how well you could ride and what a difference a proper fast ski was. Never owned another but always had a soft spot for the 550 since and always knew I’d get another.


After life took over - career, family and kids etc, I thought why not see what’s out there to buy .

Unfortunately, there wasn’t much around at the time, but I settled for a nice looking 80-90’s style Kawasaki JS440 I found on marketplace. It was a 4 hour drive out to West Queensland to meet an old timer that had owned the ski since the 90’s. Was previously owned by a helicopter pilot who had done almost everything you could to a ski in that era.

So, I snapped it up and immediately set out to just go over it all and get it running again. Well, as it had been sitting so long, it turned out everything I touched on it either needed replacing or repairing. So began a complete restoration to where it sits now.

Kawasaki JS440


I started to gather and source parts locally and out of the US where I happened to chance upon a nice rebuilt, but unfinished, reed motor with some other nice bits and pieces. Bought it all, sight unseen and began building!

Went for a complete 550sx driveline conversion, which meant sourcing a pump and converting the hull to accept the sx bearing housing. Then got to work aligning, setting up hose routing etc as more and more parts started turning up and the starting budget was shattered, haha.


Finally got all the bits and pieces required to finish it all up and get to water tuning after bench tuning and remembered one very important thing, I hadn’t lapped the flywheel!! So I began to pull the front end out to do so and noticed some light oil spray on the hull. The old Kerker pipe had cracked in a couple of places. I did have a Westcoast pipe in excellent condition but I prefer the stainless pipes personally, and after posting on the 550 JetSki page I had a couple of offers. However, in the end I was able to score a nice PJS reed pipe locally and couldn’t be happier with how it all turned out.

So it’s again complete and ready to go to water testing/tuning and jetting which we all know is the fun stuff!

Kawasaki JS440


1985 Kawasaki JS440 / 550SX
200psi on 98 octane pump gas
927 Castor 40-1

  • Rear exhaust mod
  • Match ported rebuilt reed motor
  • Duel Mikuni 38mm SBN’s
  • Billet carb coupling
  • Throttle shaft retainers
  • Westcoast exhaust manifold
  • PJS ex2550p Full Pipe
  • PJS water box

What You'll Need

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