This modification utilizes the RIVA Power Core Exhaust Insert to replace the restrictive catalytic converter while retaining the original exhaust system. The Power Core increases peak horsepower and torque. Underhood temperatures are dramatically lowered due to removal of catalytic converter. Reduced temperatures in engine compartment allow for use of RIVA Power Filter Flame Arrestor. Oil injection system can be retained and you can now use standard Yamalube Outboard Oil instead of special 2-W Yamaha Marine Oil. RIVA Cat Temp Sensor Chip is installed to prevent warning lights & beepers from activating when catalytic converter is removed. RIVA Pro-Series EFI Control Unit is installed. Unit provides easy adjustment of fuel delivery to meet the needs of modified EFI motors. Plugs directly into factory wiring harness connectors for quick installation. RIVA Cat Temp Sensor Chip is installed to prevent warning lights & beepers from activating when a catalytic converter is removed. RIVA Power Filter Flame Arrestor is installed to increase airflow to motor. Power Filter mounts easily to original flame arrestor case and permits the removal of restrictive air plenum chamber and internal OE flame arrestor screens 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. RIVA Performance Cylinder Head Kit is installed. Head features 48cc domes (including OEM gasket volume) producing 145-150psi compression (valves down). Girdled head design securely clamps cylinder down preventing potential cylinder cracking possible on modified motors.
(Note: We offer a modification service for your stock cylinder head. This consists of decking and redesigning the combustion chambers. This modification will produce performance similar to the RIVA Performance Head, but does not provide protection from cylinder cracking.) RIVA GP1300R Free Flow Exhaust Kit is installed. Kit replaces restrictive sound suppression system located between waterbox and hull exit reducing backpressure and engine operating temperatures. RIVA / Solas 14/21 'Set-Back' Concord impeller is installed. This impeller is specifically designed for the Stage II GP1300R (`03~04 models) application using a 87mm exit nozzle. RIVA GPR Billet Impeller Cone is included. Original 87mm Yamaha GP1200R exit nozzle is installed replacing the standard 85mm GP1300R exit nozzle. Larger exit nozzle compliments the 14/21 Set-Back impeller maximizing performance. RIVA GPR Performance Ride Plate and Top-Loader Intake Grate are installed. Our ride plate and intake grate combo increase top speed and significantly enhance craft’s handling characteristics. Prop spin and cavitation found with the stock grate is greatly reduced along with the modified GPR's tendency to drop on its nose when the throttle is let off at high speeds. RIVA GPR Pump Seal Kit is installed. Location specific molded inserts are siliconed in to the voids of the OE pump inlet shoe significantly reducing cavitation. RIVA GP1300R Performance Trim Tabs are installed in place of original trim tabs. Designed to trim craft up for increased top speed and serve as a quick fix to unwanted proposing. Tabs are 2.5 inches longer than stock. RIVA GPR Pro-Series Adjustable Sponsons are installed. Sponsons dramatically improve the handling of the GP1300R with a superior blade design and mounting angle. Sponson depth is adjustable to accommodate any riding style. NOTE: Stage II modification is for competition use only.
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