Regardless of the level of success that closed course, endurance, and grudge racers have achieved over the last short 7 years, Yamaha has slated the GPR for retirement in 2007. My goal is to further this platform, making it possible for this icon of the watercraft world to survive for years to come. I plan to describe how to build the specialized brackets, as well as any tricks for fitment.
I would have preferred to use a Yamaha power plant, but their own 4 stroke mill is extremely under powered to reach the goal of 75-80mph, and would have required thousands of dollars over and above the donor craft. Instead the RXP Rotax powerhead is developed and successful. Since it's hull is lacking, this project seems like a natural fit. This is not the first fitment of a Rotax SC, nor the last. Only time will tell if it works or not.
If you have interest in sponsoring this project,
with either parts or discounts, please email me at firstname.lastname@example.org
You can find ongoing updates on the following pages, along with cost and comments. I'm glad to help with your own project so contact me if you have any questions. Mark.