The Flying SHO Couch

Ski M.D. take a 381 kg Yamaha SHO and make it fly.  Feb - May 2010.

The Brief: 

We received a project outline from our customer with the request to 'modify' his brand new Yamaha FX SHO Cruiser to make it as fast as possible while maintaining stock reliability for recreational use.

Ski M.D. Basic rules of thumb.....Cheap, Fast and Reliable!!  Which  TWO  do you want?   

The customer went for fast and reliable and indicated us a budget which he could live with and into it we went.  This is a different concept for us in NZ where the only ski's we normally seriously modify are for race application and therefore we have done enough RXP and RXT hot up projects to do them blindfolded.  So there was a certain amount of eagerness to see what this plush Yamaha model could do.

The Start:

The ski was removed from the crate and run in for one hour with a GPS reading at the end of that hour of 66 MPH solid.  We then returned to the workshop and pulled this brand new ski to bits and threw about twenty kg's of OEM parts in to the bin.  Let the progress begin...

Parts Order: 

At Ski M.D. we thought we had seen it all when it comes to the price of aftermarket parts with the bad old days of the US dollar at 50 cents to it being more like 70 cents at the moment but the aftermarket manufacturers in the good old USA are sure trying to make up for the GFC with the release of bits for the SHO Yamaha's.

Our shopping list went something like this...

Riva Rear exhaust mod

Skat Prop

JE Pistons

Carrillo con rods

LA sleeves

R and D water cooling Kit ( customised by us for the application )

Rad 4 Racing Pump nozzle mods with custom reduction rings

Riva sponsons

R and D intake grate and Ride plate modified by us with increased fixing points.

Riva intercooler

Supercharger Wheel ( SKI MD )

Riva throttle body mod

Riva air intake tube and custom filter

Motec ECU as a total replacement for the factory ignition and fuel control system.

There was about 30 hours work on the engine with machining of the engine block and install of the sleeves completed at Marsh Motorsport  Tony is an expert in quality engine machining and always excited to work on new projects with us.

The engine block then returned to us for careful assembly prior to install. Once the engine was in the hull we spent a week installing all of the aftermarket components and modifying them in some cases to our own liking and specification.

Start up day had a few challenges with the Motec being a new science for me but with the help of Mike and Sue at Reaction Racing , we got a start up and made plans to take it to the river for initial run in and tune up.

Tune up of the fly by wire set up on the Yamaha was a hell of a lot easier with the Motec data logging giving us a full readout of each run by the millisecond and with Mikes expert skills in tune up and analysis, we had a tune in the ski good enough to complete the run in prior to the final tune.

I have ridden this ski now for about five hours and find the Yamaha SHO Cruiser to be the best hull on the market with a smooth predictable ride over the rough and it turns on a dime with the handling package we have fitted.

Final tune prior to delivery to the owner was done and the numbers are to say the least "impressive" This couch flys! . The ski will appear at this years bridge to bridge race with the owner on board and he will definitely be a top five contender. I will report the numbers I know you so want to read after that event but over 80 MPH on pump gas for now is not a bad result. The ski is now doing recreational duties until November so watch this space for long term reports.

28 November 2010  Successfully took 2nd place at Hamiltons Bridge To Bridge  - beaten only by Ski M.D's GPR conversion ski which is one of the fastest in the world.  People in the crowd were shocked at this large recreational PWC flying past them to the finish line at approximately 86 mile per hour.



Studio SHO