Big things come in small packages
Especially if you’re really, really innovative.
And innovative happens to be Jamie Eade’s middle name.
Eade, who has two decades of experience as a fuel injection specialist and dyno tuner, working in motorsports, operates one of Australia’s biggest Kawasaki dealerships, Brisbane Kawasaki, and is also the man behind Kspeed, bought a brand-new Kawasaki STX 160LX and an Ultra 310 crate engine out of the US – minus the supercharger. He then took a brand new supercharger from Kawasaki Australia, sprinkled in some blood, sweat, tears and magic – And came up with the 2020 STX-310LX (PROTOTYPE).
Joshua Dowling tested out the 80-mile per hour Ultra-powered STX310LX for The Watercraft Journal in September 2020, concluding that “With 310 horsepower on hand, however, (the Ultra-powered STX310LX) commands respect and elicits a healthy dose of fear. Macho-types in the jet ski community might be dismissive of so much grunt in such a small package, but we’re here to testify that this thing demands your full attention. So it bears the question: is 310 horsepower too much for the STX? In a novice’s hands? Yeah, probably. But in experienced hands, it feels like the sky’s the limit with this machine.”
A short while later, WCJ promoted a video of the STX310LX featuring a walkthrough by Eade himself, and in June of 2021, WCJ took a second look at the ski through the eyes of Greg Gaddis, who noted “Kspeed’s STX310LX is a fully functioning watercraft with electric trim, stereo system, and a display from a 2019 Ultra 310. Surprisingly enough, this conversion was built with almost all original Kawasaki manufactured parts. With only modifications needing to be made to the pump shoe, airbox bracket, and intake hoses, this is otherwise a bolt-on installation when utilizing original parts dating back to the Ultra 250. The result is a lightweight, nimble, and 80mph-capable watercraft out of the box.”
And yesterday, Brisbane Kawasaki announced, “The time has come to move this very special ski on, so we can make way for a new project”
Which means, this powerhouse can be yours for $18,189, or $19,728 for the ski and trailer package (not including shipping).
For more details, see the full listing from Brisbane Kawasaki below.
In March 2020 when the world was at it’s knee’s and everybody was closing their doors, staying home and trying to make it big on TikTok, We decided to stay open (as an essential mechanical service) and do something with our time.
Now a few years prior we built a Frankenstein STX15F with a 250X motor shoehorned into it. It was a ski that looked terrible but when you pulled the throttle it stood up and launched into the air giving the rider the feeling of a wheelstanding superbike.
We mothballed it as we knew we physically couldn’t fit a 310 motor into this hull, but the idea never left our minds.
October 2019, Jamie was in the USA for the launch of the all new STX-160. He took his tape measure with him and when no one was looking stuck his head and phone in there and took some very important measurements. (It was going to fit)
Our STX’s arrived in Australia Early 2020, just prior to Covid becoming a big deal. By March it was here and the shutdowns began. We stayed open and used this downtime to finally make this happen.
We studied the service manuals of both the 2019 Ultra 310LX and the 2020 STX-160X outlaid the wiring plans to make sure we weren’t going to miss anything.
First things first, we uncrated a brand spanking new 2020 STX-160LX, removed the seats and yanked that motor, dashboard, exhaust system, running gear & jetpump out of there.
We were left with a bare hull, keeping just the fuel tank, and handlebar controls.
Next we pulled apart our 2019 Demo Kawasaki Ultra 310LX, and fitted those parts directly into the stx hull. We needed only a few minor parts to be custom made (pump shoe, air filter mounts and some silicone pipes), we used a ultra 300 exhaust system. The dash cluster bolted straight in and then we changed the connector over to retain the fly by wire throttle (which we later scraped in favour of the ultra 310 cable unit that wasn’t so touchy)
We bolted it all together, wired it up (and yep we even got the OEM stereo to work).
We all drove down to the local creek and took turns running it in on the SLO key eager to see what this could do. After 2hrs of being extremely nice to it, Jamie jumped on and did his very first WOT pass. 128kph…. Wowsers. Stock everything with only a delimiter in the ECU. Insert Tune. 131kph (80mph baby)
We did it, a STX310 that easily touches the high 70’s and in the perfect conditions goes over the magic 80. We gave it the Kspeed treatement. Kspeed ride plate, Kspeed intake grate, Kspeed sponsons, Kspeed cool air intake. Kspeed 108mm pulley, Now it handled like it was on rails and hooked up far better. Acceleration from 20-30kph was insane but getting it off the mark proved a little trouble some, so we took the pulley back off and that made it more pleasant to ride.
Jamie has entered this ski in a few QPWC closed course events and it’s held it’s own.
We have left Jamie’s 888 racing numbers on the side for now as he really doesn’t want to part with it, but for the right money you can own this one of a kind Prototype Jetski thats been seen by people all over the world and featured in The Watercraft Journal.
