RIVA / Boyesen Reed Stuffers are installed into stock reed cages with stock reed petals. Stuffers increase fuel / air velocity through intake tract, resulting in increased throttle response and acceleration. "Tamper Caps" are removed from high and low speed carburetor adjustment screws to optimize carb settings. No internal carburetor modifications are performed.

RIVA Performance Cylinder Head is installed. Head features 41cc domes (including OEM gasket volume) producing 145-150 psi compression (valves down). Girdled head design securely clamps cylinder down preventing potential cylinder cracking possible on modified motrs. Requires use of 92+ octane pump fuel.

Note: RIVA also offers a modification service for your stock cylinder head. This consists of decking and redesigning the combustion chambers. This modification will produce performance similiar to the RIVA Performance Head, but does not provide protection from cylinder cracking.

RIVA Cat Removal D-Plate is installed in place of restrictive catalytic converter increasing top-end speed while reducing under-hood operating temperatures and allowing the use of regular 2-stroke oils. Our D-plate is a high quality stainless steel replica of the plate that is standard equipment on export model Yamaha watercraft without emission controls.

RIVA Cat Temp Sensor Chip is installed to prevent warning lights & beepers from activating when catalytic converter is removed.

RIVA XLT Ride Plate and Top-Loader intake Grate are installed. Our ride plate and intake grate combo increase top speed and significantly enhance handling characteristics. Prop spin and cavitation found with the stock grate is greatly reduced increasing acceleration and hook-up.

RIVA XLT Pump Seal Kit is installed. Location specific molded inserts are siliconed into the voids of the OE Pump inlet Shoe significantly reducing cavitation.

Solas 12/18 Concord impeller is installed without washer/spacer. Eliminating washer/space allows impeller to move closer to vein housing providing improved top speed and reduced prop spin.

RIVA Performance Pump Cone is installed in place of stock pump cone on jet pump vein housing. Pump Cone significantly reduces cavitation due to its innovative design and asymmetrical shape that matches the angle of stock Yamaha pump nozzle.Billet Impeller Cone is installed in place of rubber Solas impeller cone that can blow out causing cavitation.

RIVA XLT Pro-Series Adjustable Sponsons are installed. The sponsons dramatically improve the handling of the XLT with a superior blade design and mounting angle. Sponson depth is adjustable to accommodate riding style.

NOTE: Stage II modification is for competition use only.