If there is only one thing that you take away from this review, it should be that Kawasaki’s 2015 Ultra 310R JetSki makes a lot of power. A brutal, rotator cuff-tearing amount of power. If you’re not ready for it, not properly conditioned both mentally and physically, it will fight you back… And make no mistake, the 310R will win. So much so that we toyed with the idea of naming this review “Corporeal Punishment.”
Last year marked the introduction of the R-class Ultra and its lauded 310-horsepower. The jump from 300 to 310 ponies was not merely an advertising ploy by Kawasaki to push ahead (way ahead) of the competition, but rather a happy accident. By radically improving engine oiling, reducing heat soak and lowering internal engine temperatures throughout the engine’s powerband, Kawasaki managed to free up the extra power by making major improvements in the engine’s efficiency.
The 1,498cc, 83.0 x 69.2mm (bore x stroke) liquid-cooled inline four-cylinder received a newly re-engineered crankcase with thicker water jackets, larger oiling passages for quicker oil return to the redesigned baffled pan that reduces oil windage and sloshing, a second sprayer to each under-piston cooling oil jet comprising a semi-dry sump system, new lightweight 8.2:1 cast pistons featuring additional ring land V-grooves, a larger capacity fuel pump and 500cc injectors.
Last year’s supercharged Ultra also got a brand-new long-runner intake manifold made from heat-resistant plastic, fed by an Eaton TVS constant-displacement, four-lobe supercharger pressing 16.8psi past two blow-off valves. And speaking of valves, new hardened nickel 33.4mm intake and 28.3mm exhaust valves ingest and expel the spent fumes.
Above: Engaging No Wake mode is effortless compared to setting Cruise Control, which we struggled to master. While cruising past the No Wake buoys, the Ultra tracks smoothly and dryly – with no nose-plowing. We noted that adjusting the trim requires holding down the toggle, something we marked as bothersome particularly while on the move.
Other goods included a large oil breather/catch can and articulated sprung belt tensioner, and a check valve system fixed between the cylinder jacket and water muffler that shuts water flow off above 2,000rpm, keeping the cooling water inside the cylinder jacket for optimum cooling performance. Finally, a voluminous 160mm 8-vane pump houses a repitched 3-blade long-snout prop.
The 310R gained a new Sportseat, wrapped in a grippy textured canvas and a molded Hydro-Turf traction mat kit. One final addition to the R-class was a fixed electro-polished stainless steel steering neck and race-grade MX-style handlebars replacing the standard tilt steering. These new MX bars can be adjusted fore and aft by loosening the hex head bolts to 12 different positions.
The changes made to the 2015 310R are miniscule but intentional: First, a mid-production adjustment was made to the big 1,498cc’s engine management program during last year’s run that is now standard on all Ultras. (Contrary to claims that a new ECU was introduced.) Next, tweaks in the race bred Ultra’s livery – namely the change from 2014’s blue pinstripe to silver, and the almost boring “Kawasaki” hood decals – were made to accommodate racers who replace stock graphics with race numbers and sponsors’ decals.
A final, albeit purely aesthetic change, are the addition of green sponsons. Literally identical to last year’s and to other 2015 models, the choice to make the 310R’s sponsons green is elusive, if not as purely a conversation piece. Although they’re fixed in position, they offer measurable traction in tight turns, even throughout the Ultra’s 5-position electronically-adjustable trim settings. Other controls include Cruise Control with accompanying toggles, 5mph No Wake mode and Kawasaki’s own take on Eco mode.
Beneath the glove box door is a capacious bin that combined with the underhood stowage equals a class-leading 56-gallons worth of storage, and the keyway ignition for a choice of Kawasaki’s yellow SLO (Smart Learning Operation) to reign in the Ultra’s throttle, or the normal use green key, which unleashes the 310R’s full fury. Even with Eco engaged, throttle response is taut if not only slightly muted from standard operation, and capable of top speeds in the low 60s.
When released from its Eco setting, the whine of the JetSki’s Eaton supercharger is only dwarfed by the whistle of wind blowing past your ears. Launching from a crawl, the Kawasaki comes to plane in seconds, its 22.5-degree deadrise sluicing through chop like Luke Skywalker’s lightsaber. At wide-open, the blown 4-stroke four-cylinder propels a single rider to 67.2mph with bravado.
A day spent behind the bars of the 310-horsepower Ultra will be one of face-stretching acceleration, and knee-in-the-tray hairpin turns that will kick up Gibraltar-sized walls of seafoam with every corner, not to mention maybe one or two stops at the fuel dock. With all that power comes not-so-great fuel mileage, and the 310R’s 20.6-gallon tank will surprise you with how speedily it can be drained.
We attribute a fair amount of that unquenchable thirst to the Ultra’s shotgun-like throttle response. Again, acceleration comes on strong behind the bars of the 310R (and not without some recoil), and easing the fly-by-wire trigger takes a great deal of finesse and restraint. Truly, the 310R’s throttle not only manipulates the Ultra’s big 60mm throttle body, but also your brain’s endorphins.
We took particular note of the 310R’s redesigned seat, as its low bolster is slightly set further back than the big scallops of the luxurious 310LX and is narrowed at the knees compared to standard 310X’s. The grippy material offers plenty of bite without irritating exposed skin as well. Taller riders might struggle with the low slung position of the bars (ideal for seated closed course racing, rather than standing upright for offshore riding).
Of course, such minor quibbles pale in the shadow of the 310R’s true purpose. Even in light of its 1047.4 lbs. curb weight, the 2015 Kawasaki Ultra 310R’s horsepower will hit you like a hammerfist. It will cut turns like a steel tracked rollercoaster and it will blast through lake chop like a heated knife through room temperature butter. As far as watercraft go, there is no Kawasaki more unapologetic for being this punishing to your senses. The sights, sounds and sensations conjured by the Ultra 310R can be overwhelming to lesser men. We suppose that is why we love it so much.