Re: Any aftermarket parts available for '94 WRA700S Waverunner?
Sorry - I forgot that they went to a 701 motor in 94 - I had looked up the model number and saw it was a WRIII.
that opens up your possibilities with what you can do with it - all depending on how much you want to spend on it, and how comfortable you are with doing some work yourself:
mill the stock head, or purchase an aftermarket head with smaller domes (gives higher compression)
advance timing
buy a replacement ignition such as an MSD, or modify your stock CDI to increase the rev-limiter
replacement exhaust (Coffman's, Factory Pipe, Riva or others)
engine porting
there is some gains realized by pump blueprinting as well. A different impeller than the stock one will wake it up also.
One thing that can be done easily (and free) is to remove and disable the stock overheat sensor. It's on top of the head near the rear of the ski, held in place with a small bracket. remove screws, trim wires all the way back near the e-box. strip the wire ends and twist them together. then dip the whole thing into liquid electrical tape several times. This will give you a bit for "zip" - but it also prevents the engine from operating in "safe mode" if it overheats. There is a danger you could overheat your engine by doing this modification.
My experience is with yamaha 2cyl motors (6m6 - 650, 61x and 62t - 701, and 760) in stand-up skis so I can't recommend specific things for you to modify as I have different performance goals on a stand up than you would on a WRIII, but the things I mentioned above are all applicable to your engine to some degree.
This forum is really not the best place to get performance advice.
www.pwctoday.com (general PWC) or
www.greenhulk.net (performance sit-downs) or
www.x-h2o.com (all things stand-up related) are better places to get that type of info.
you should also realize that as you get into modifying your ski, you likely won't get that money back if you go to sell it, unless you part it out. Keep that in mind.