Months before other dealers and the media had seen the new Yamaha VXR models, Riva Motorsports  was tearing a prototype apart, trying to figure out how to make it go faster. And in January, Riva will offer a hop-up kit for the VXR it claims will offer a gain of 25 horsepower and five mph in top speed.

A new performance kit from Riva Racing promises to boost the performance of the Yamaha WaveRunner VXR and VXS models, with a jump in top speed from 68 to 73 mph.

Through its Riva Racing division, the Pompano Beach, Fla., motorsports dealership has been a Yamaha WaveRunner performance merchant since 1993, and for several years managed the Yamaha Factory Racing team. It’s that close relationship, and the shop’s expertise, that gets it an early look at many new Yamaha products. Formally called the Riva Racing VXR RPM Kit, this package of performance upgrades includes seven items.

A K&N filter/flame arrestor mounted to a new bulkhead draws cool air vented to the bow storage compartment of the Yamaha VXR.

A key item on that parts list is a new Power Filter Kit intake system that draws cool air from outside the engine compartment. The intake utilizes the open vent grille in the stock VXR cowl to feed air into the bow storage compartment. A molded plastic water trap that is part of the kit redirects water that might enter the vent down to the bilge and away from the engine intake. A new Riva bulkhead replaces the stock bulkhead that fits between the storage compartment and the engine bay, and holds a high-performance K&N filter/flame arrestor. Air flows to the engine through this filter and four-inch-diameter, smooth-bore ducting that is secured to throttle body with a velocity stack and sturdy billet clamps. The aim here is to serve the engine cooler air, which has higher oxygen density and thus will allow the engine to make more power. Bamdas says he thinks this set-up is the first true cool-air intake devised for a watercraft.

Riva kit includes this molded plastic water trap to direct spray away from the intake filter.

The rest of the VXR kit is typical of other Riva kits, and includes an intake manifold upgrade kit (which removes the stock flame arrestor to reduce intake restriction), a free-flow exhaust kit that reduces back pressure by eliminating the sound suppression system located between the water box and hull exit, a new top-loader intake grate and a performance ride plate, a Solas Concord impeller, and a pump seal kit that keeps air from bleeding into the pump housing and causing cavitation. Each of these kits can be purchased separately.

Components of the Riva Racing Power Filter Kit for the Yamaha VXR/VXS.

Bamdas says the kit comes with complete instructions and can be installed by a competent do-it-yourself owner in about six hours. It can also be installed by a Riva-authorized dealer for an extra charge. The Yamaha engine management system will self-adjust to the changes in intake and exhaust flow, so the ECU does not need to be reprogrammed, according to Bamdas. The engine components of the kit take the 1.8-liter engine from about 180 horsepower to about 205 horsepower, and Bamdas says top speed should increase from about 68 mph to 73 mph, with a “significant” improvement in acceleration. The kit can be installed on either the VXR or VXS model, which are identical except for the seat.

To shop for Riva Racing Performance Kit for Yamaha VXR and a K&N filter/flame arrestor  check out our sponsor partspitstop.com