Kawasaki riders find comfort in their speed
5/26/2004 12:12:06 PM by Marshall Brodie
Can a personal watercraft be designed for ride and comfort as well as speed and handling? This is just what Kawasaki has tried to do with its top-performing four-stroke for 2004, the STX-15F.
Indeed, the STX-15F is a well-balanced three-passenger craft that makes few compromises. One would expect to give up some speed and handling in choosing a three-passenger personal w a t e rcraft (PWC), but the STX-15F is comfortable, fast and nimble.
Power comes from the smaller fourcylinder four- s t roke engine used in its Jet Ski STX-12F. Kawasaki lengthened the stroke by 13.8mm to increase displacement to nearly 1,500cc. The longer s t roke provides a flat torque curve for smooth acceleration at a wide range of speeds.
This dual overhead cam, four-valve per-cylinder fuel injected engine produces 160 horsepower without need for supercharging or turbocharging. Kawasaki also made other changes to the intake manifold, valves and timing settings.
Power delivery is smooth, quiet, responsive and economical, and it is clean running. Kawasaki says the engine has earned a Three-Star UltraLow Emissions rating, the Environmental Protection Agency's highest standard.
The hull of the STX-15F is based on the Jet Ski 1200 STX-R that won a national championship racing title earlier this year.
I did 25 miles of riding on the STX1 5 F, riding through a range of conditions from choppy to smooth, protected waters near St. Petersburg. It felt light and nimble but comfortable. In areas of calm water, it was fun for aggressive maneuvers; it cornered tightly and was stable at high speeds.
Looking for speed? It had a GPS measured speed of just over 62 mph.
In rough waters, the ride was wet but any PWC would have been on this blustery day. The hull has molded-in splash deflectors to help keep the ride dry.
Kawasaki's "Smart Steering" system monitors throttle and steering and will react with increased engine rpm if the operator panics and lets go of the thro ttle in an emergency turn. Unlike propeller driven boats, jet-drive crafts must have sufficient rpm to maintain steerage; let go of the throttle and it will not turn.
A reverse lever allows for easier docking or maneuvering in tight quarters. Kawasaki raised the handlebar and moved it back slightly to accommodate a wider range of riders, which also made it easier to stand for long periods while running in rough water or for aggressive riding.
No trim adjustment is provided and it did not seem to be needed under calmer conditions.
A multifunction LCD panel monitors speed, rpm, overheat alarm and fuel level. It also has a trip computer.
Stowage includes a large bow compartment, glove box and additional space under the aft seat. The redesigned bow hatch is supported by hydraulic strut that makes it easier to reach into the compartment.
The rear deck has plenty of room to strap on a cooler or for getting in or out of the water via the retractable boarding ladder. Foot rests help stabilize a rear-facing spotter when pulling a skier or tuber.
The sport seat is comfortable and supportive enough but is not as plush as several others in this segment.
A 16.4-gallon fuel tank should provide plenty of cruising range for a full day on the water. The engine compartment leaves little room but regular access points are easily reached. The water-jacketed exhaust system and double water-box mufflers keep noise and temperatures down.
A "tip-over" sensor detects if the STX-15F tilts more than 61 degrees and shuts down the engine. And, a dry sump oil system prevents oil from flooding the crankcase in case the craft capsizes.
The Kawasaki STX-15F, priced at $9,799, achieves a good balance of performance, features, room and comfort. It is not as soft riding as Yamaha's FX C ruiser or Sea Doo's GTX-4TEC, but it still is comfortable enough for touring.
For more information, call Kawasaki Motors Corporation at 949-770-0400 or go to the website at www.kawasaki.com.
Marshall Brodie writes about boats for the Herald's Wheels & Waves section. He can be reached by e-mail at mbboating@yahoo.com.