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.
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 and will have a combined retail price of $1,569.65, according to Riva owner Dave Bamdas.
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. A downside of the Power Filter Kit is that is takes up most of the storage space in the bow compartment, but Riva will offer a $65 kit to add a four-gallon storage bin under the rear seat area.
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.
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.
I thought the VXR was a performance bargain when I reviewed it a few months ago. Bolting on this Riva kit will take a VXR or VXS to the next level, at a total price that’s still less than some new high-performance models.