It’s Easy Being Green

What Made Kawasaki Dominate the World Finals This Year? We Found Out for You.

Text and Photography by Vasilis Moraitis

Kawasaki dominated the Pro class this year, clinching World titles in three out of four of the major Pro classes in Pro Ski, Pro Runabout and Pro Am Women Ski. This was a tremendous success that proved that the Japanese manufacturer still has the winning recipe.

For this year’s test ride, the Factory Kawasaki team provided me with two of Craig Warner’s winning runabouts: last year’s successful supercharged STX-15F and this year’s winner, an all-new supercharged STX-R (featuring a unique, custom-fabricated Ultra 250X hull with a 15F deck). Italian veteran Alberto Monti, who won the Pro Ski class, was leaving immediately for Europe, inhibiting me from riding his winning SX-R. On the other hand, I did get to ride Steven Dauliach’s and Jean Baptise Botti’s SX-Rs, not to mention Emi Kanamori’s factory Limited SX-R.

Craig Warner’s Factory Kawasaki Jet Ski STX-R

Last year, what the Factory Kawasaki team had in mind was reliability, which held precedence over extracting more horsepower out of the 1500cc powerplant. This year, Team Green developed something totally new, altering an Ultra 250X hull to mate with the ergonomics of the tried-and-true STX-R. When I first saw the two Kawasakis – last year’s 15F and the new STX-R – I was initially confused with the shape of the modified hull.

After spending lots of time observing every single detail between those two hulls, I took out my measuring tape and started measuring the two at the front and rear, because something did not sit very well with me. Even the Kawasaki team manager, Joe Heim, wondered what I was doing. Soon after, I realized that they took the Ultra 250X hull and removed the deck straight from the bond flange, significantly altering the weight distribution and the ergonomics.

Enginewise, there weren’t many changes from last year. The STX-R retains the Ultra wiring harness, a change from last year designed to equip the 15F engine with a boost-pressure sensor as well as a sensor for the inlet temperature. Additionally, the factory crew installed a new electronically programmable Mitsubishi ignition. According to Joe Heim, there was a lot of programming involved in bypassing the immobilizer.

The key to the supercharged engine is the belt that activates the compressor. Precise belt tension plays a critical role in the overall performance. A serpentine-belt drive provided satisfactory performance, strength and durability. Additionally, the STX-R uses a modified Riva supercharger bracket. A Sato Engineering silencer proved to be strong and dependable. With all of this equipment, Heim reported a stable 380 hp.

Team Kawasaki used the same trim system as last year, consisting of a narrow trim tab fitted at the rear of the ride plate. Due to the severe forces acted on that edge, the team installed a pneumatic system to activate the tab to minimize effort and rider fatigue. The updated pneumatically actuated trim tab system was equipped with a smaller air canister. Additionally, an aluminum frame was made to accommodate the canister and the Mitsubishi ECU. The new construction helped to keep weight to a minimum.

The pump and drive system were mainly retained from last year’s race craft. A 160mm Skat-Trak pump took the place of the OEM pump. This year, a 14-vane pump was used instead of the previous 12 vane. A Skat-Trak three-blade impeller with a special “Havasu pitch” was custom made to provide an acceleration advantage without sacrificing too much top speed. A Riva steering nozzle equipped with an auto-drop nozzle system was mated to the pump. According to most riders, these nozzles provide a better feeling compared to the Skat-Trak. The STX-R’s drop nozzle is activated by a Kawasaki MX-type trim lever.

The ride was carried out around 9 in the morning at Body Beach in slightly choppy water – perfect to put the racecraft to the test. I hit the green button and immediately felt the purebred, factory-supercharged engine thundering under the newly modified carbon 3DR seat. The seat was altered in order to stop Warner’s body from sliding under acceleration.

In general, the STX-R ergonomics have been changed dramatically. You sit high on the saddle – not in it – like riding an Ultra 250X. This riding position gives you a better feeling and enables you to apply force on the handlebars more aggressively. The steering system has been modified, too, with the stem being cut and welded further back, placing the steering axle 30mm further back.

The unique thing on the craft is not just the sharp, strong acceleration but also the precise handling. The harder you push it around the buoy, the harder it hooks up. Yet, it tended to highside you if your mind was elsewhere. The nose of the craft was kept down at all moments without having the tendency to rise like the stock Ultras. The hull kept hooked up no matter how sharp the turn. Going around a 90-degree or a hairpin turn was a piece of cake. The only thing that I had to do was to place my body in the right position and the Kawasaki handled like it was on rails.

The hull has kept its original Ultra handling DNA, making life easier for its rider in rough conditions. It still felt heavy, a lot heavier than any other Factory Kawasaki I had ever ridden in the past. I felt safe no matter how fast I was approaching the buoys. The G-forces were reduced compared to the 15F package I rode last year. The prototype R&D ride plate and intake grate helped, providing a lower planing attitude for better turning.

Under these conditions, there was no need to use the pneumatically activated trim tab since it wouldn’t have made much difference, although Warner insisted that it helped during the race. The steering system provided smooth operation without showing any signs of tightness before reaching the stop from side to side. Although the engine acceleration has been improved a lot (theoretically) since the ’04 edition (with no flat spots or any sign of hesitation), the new STX-R proved to be heavier.

According to Joe Heim, the weight difference between this STX-R and last year’s 15F is around 40 pounds. Warner informed me that this 15F package was much faster in both acceleration and top speed. According to Kawasaki’s readings, Warner reached a top speed of 78 mph. The hull setup was made in such a way to sacrifice some top speed but gain in turning around the buoys. Joe Heim assured me that it is possible to extract a lot more speed out of it, a secret that he is probably keeping for next year.

Emi Kanamori’s Factory Kawasaki Jet Ski Limited SX-R 800

Since 2003, the competition has risen enormously in the Pro Am Women’s class at the World Finals. We have seen breathtaking passes and fiberglass-rubbing that prove women are just as determined to win as the men. Their craft are on a Limited spec, which means that, for a tuner, a lot of hard work is needed to dig up the needed horsepower.

I have ridden quite a lot of the women’s Limited skis the last five years, and while some of them share the same aftermarket parts, the power delivery and acceleration differed among all those skis. I’ve been trying for years to ride Emi’s Kawasaki for two reasons: First, because she is, without a doubt, one of the fastest riders out there. And secondly, because her husband is the well-known Kawasaki mechanic and test rider Minoru Kanamori.

Emi’s setup has not changed much since last year. Minor modifications were made to enhance aesthetics and reliability. Her new black anodized SE handle pole came straight from Seiko Osawa’s race craft and the hood insert is a new carbon piece made by SE. Emi’s hull retained the front sponsons from last year, enhancing straight-line stability and cornering. She kept the Craftsman’s carbon ride plate as well as the TBM intake grate. This particular plate is longer than other aftermarket plates and is commonly used by Japanese riders.

On the driveline, Minoru had installed a Skat-Trak 140mm, 12-vane Magnum pump along with a drop-nozzle system. A Skat-Trak 15/20 swirl impeller with a medium pump cone was used to unearth some extra power. Emi kept the OEM siderails choosing to use a Jettrim mat and gunwale pads. To enhance the ergonomics, Minoru installed an SE handlepole, along with an SE steering plate and 4-degree UMI Racing bar. The stock trigger throttle has been replaced with a first-generation SE one, while the trim lever came from UMI Racing. The OEM hood was modified to fit with the aftermarket exhaust pipe.

The SX-R powerplant uses 82.75mm Kawasaki pistons to fill the largest possible bore – according to the new IJSBA rules. Minoru fit an SE billet-aluminum cylinder head with 25cc domes to raise the compression to 195 psi. A set of 48 Novi carbs feed the engine through V-Force 2 reeds. The carbs are mounted on an R&D manifold and are topped with R&D filters. A Factory Pipe dry pipe was also fitted. Kanamori has paid great attention to the cooling system, since it plays a central role to the performance of the Limited package. Therefore, he uses one 3/8-inch cooling line that feeds the rear cylinder and one half-inch line that splits into another half-inch line, going straight to the exhaust manifold, while the other is a 3/8-inch line that feeds the exhaust chamber. The chamber temperature is very critical since it alters the speed of the sonic wave.

After making a couple of laps, I noticed that Emi’s SX-R came on strong from a very low rpm while last year’s model kicked in hard just before the midrange. At very low rpm, the engine response was sharp and the power being translated into thrust was immediate. The motor felt more torquey, allowing you to enter the buoy much deeper and press the gas without losing time. Minoru assured me that this craft reached 59 mph, and I believe him, since he is the man that carries out lots of testing during his daytime job.

The handling was precise and predictable. The craft was stable in the straight and I did not have to use the manual trim to push down the nose; the long ride plate did the job. Additionally, it provided good grip in the hairpins or in high-speed turns. The front sponsons were set to enhance the hull’s leaning ability in the entrance of the corner, providing greater stability and drive when I was approaching the buoy. The pole and the steering system were not too tight, nor too loose, but somewhere in the middle – a comfortable setup that provided good feeling and required less rider input. Overall, the engine-displacement upgrade made a big difference to the power delivery and also enabled Emi to ride it smoothly under the demanding conditions of that particular race.

Steven Dauliach’s Kawasaki Jet Ski SX-R 800

Thanks to a rule change for the Pro Ski class in the way of added displacement, the sport’s top tuners had the opportunity to explore new approaches in finding more power from the Kawasaki.

This year, Dauliach’s builder, Steve Webster, used a billet stroker (4mm) crank equipped with special bearings that withstand the extra load produced by the larger motor. Heavy-duty connecting rods topped by special Wiseco pistons and rings completed the reciprocating assembly. Webster prepared four engines with two different setups. The crankcases and the cylinder were ported specifically to meet the new parameters of the crankshaft. The cylinder was topped with a JSU billet-aluminum cylinder head with 28cc domes – a setup, that, along with the thick base gasket, raised the cranking compression to 205 psi.

Webster used a fuel intake similar to last year’s setup, with major changes to the reed cages and the air filters (the first ones were a set of Moto Tassinari V-Force 2, and the latter was a pair of R&D filters). New-generation Novi carbs feature booster venturis that enhance fuel delivery. A new Factory Pipe dry chamber with bigger volume and different angles exhales through a modified OEM waterbox. Webster modified the stock expansion chamber according to the big-bore requests, a job done entirely in-house (and is offered to customers). Also, he sealed the header-expansion joint with an X-2 rubber hose.

A custom-made, total-loss programmable Mitsubishi ignition was specially made in Japan through cooperation with the Factory Kawasaki team. This ignition system was an actual prototype, an Ultra unit programmed to operate for a twin-cylinder engine. A special lightweight flywheel was supplied along with the ignition system, too. Webster mentioned that he used last year’s Motzouris’ curve for this particular setup.

Webster altered the pump and driveline system with a new 14-vane setback Skat-Trak Magnum pump and a stainless-steel Skat-Trak Swirl impeller. Webster installed a set of front sponsons to the hull to enhance straight-line stability and drive through the turns. A new JSU intake grate was designed by Webster and manufactured by Skat-Trak. The steering assembly was similar to last year’s spec apart from the drop nozzle. Initially, he used a Skat-Trak long drop nozzle that was shortened at the end. The only noticeable difference in the handlepole setup was that Webster fit the twin-hole RRP pole bracket to supply the engine compartment with more air.

When I ignited Steven’s stroker engine, I noticed that even the sound of it was different from last year’s package. The engine revved much easier and was crisper at low and mid rpms. The motor pulled hard from idle and through the midrange, I could feel it getting stronger up to the red line. Steven likes to accelerate hard while exiting the buoy, therefore, Webster made sure that there was lots of torque.

The steering system (pole, bars, etc.) was not as stiff as last year’s for Dustin Motzouris’ SX-R. The new hull setup had improved straight-line stability a lot at high speeds, as well as the entry lean angle of the craft during cornering. An expert might get highsided if he were tired or not concentrating. I was able to flick it from one side to the other before I even thought about it. I was leaning the SX-R accurately with pure confidence and with no fear of submerging it.

I was accustomed to the Macc Racing ride plate, since I have used it extensively in the past. Steven was one of the first to use it on his JFC Team-prepared race craft and continues using it to this day. The nose was kept down most of the time, no matter how hard I pressed the gas. Actually, Webster told me that Steven had even put shims in the ride plate to keep the nose down further. It took a while for Webster to persuade him to change his original setup to this.

Overall, Webster has made a substantial improvement to the tuning of the SX-R this year. The SX-R proved to be very fast but still easy to ride, a user-friendly racecraft that any racer could adjust to within a few short laps.

Jean Baptiste Botti’s Kawasaki Jet Ski SX-R 800

Last year, while hanging around Performance Alley during the World Finals, I bumped into Pascal Barriac at Fennec’s booth. As he asked about the price and availability of the new short-block Kawasaki billet-aluminum cylinder and head unit on display, I immediately knew what Barriac was planning for next year...

And true to my prediction, Barriac used the Maekawa top end (a billet-aluminum cylinder with pneumatically powered valves and cylinder head) as the main components of his new setup. Barriac altered the port timing to bring it to a more desirable level, as the engine employed a stock Kawasaki crankshaft with OEM crankcases. The ignition system consists mainly of factory Kawasaki parts; it’s a total-loss unit with a programmable Mitsubishi ECU. Barriac was one of the few in the world that was able to get one from Team Kawasaki.

The trickiest part of the engine is the exhaust pipe. At first glance, it resembles the one-off unit that Ross Liberty had made for Malone’s big-bore motor back in 2005, although Liberty’s carried a Pro Circuit sticker on the expansion chamber. A reliable source informed me that Mark Baxter, ex-employee of Factory Pipe, had the tooling to fabricate such a pipe for Barriac.

The new pipe required the fuel tank to be moved further to the back, between the expansion chamber and motor. Since the OEM water box was ditched, a smaller inline muffler was used to cut down the engine noise. On the intake, Barriac used the usual recipe of Novi carbs with an R&D intake manifold. The carbs draw fuel from the OEM tank through a Cold Fusion dual pickup. The tank was secured to its new place by extra elastic bands.

Botti’s hull had actually the most aggressive setup of any stand-up I’ve ridden in the last three years. The main difference between this and other stand-ups was the heavily modified R&D superstock ride plate and tricky Skat-Trak intake grate. The latter was very similar to the one that Botti was using back in 2005. The R&D ride plate was modified according to RIVA specs, a design that the company used in the early ’90s.

Barriac designed his own hood for the SX-R that carries similarities with the ZEN hood that Team Kawasaki was using in the late ‘90s. It utilizes larger air ducts to bring more air to the engine compartment. The dual inlet RRP handlepole plays the same role, topped with the newest dual-intake RRP pole pad.

Botti’s SX-R was a real beast, accelerating sharply with absolutely no hesitation. The big-bore engine sounded hungry underneath the lightweight hood. The hull hooked up so nicely that I was able to get back on the gas even on maximum lean without losing grip.

The harder I was riding it toward the buoy, the more aggressively it was responding. My heartrate started rising and there was a moment I thought I was going to highside, but luckily I managed to keep it together. The steering system (turn plate and handlepole) was not too tight – as some of the racers prefer to set it up.

Still, I wonder how Botti managed to deal with this aggressive setup under this year’s brutal race conditions. Barriac chose not to mention Botti’s top speed, for obvious reasons, though I do remember how Botti passed Dauliach in the second moto of Pro Ski. Since I rode it right after Dauliach’s SX-R, I believe that the top speeds of the two are very similar, while Botti’s pulled harder out of the hole. This is a true racing SX-R and only a top-level rider can ride it to the limit.