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Jet ski speed...

Posted: Thu Sep 06, 2007 8:47 am
by petersjoe
I am beginning the initial stages of my Flying Saucer build. While planning to use a jet ski engine, I will have to modify the cockpit position. However I am looking for some info on how the boat planes, and what type of speed is expected or resulted from putting a 650 in a 12'-14'boat? Depedning on how prior builds have planed I would like to adjust accordingly. I am looking for 25mph+. In anyones opinion is this possible?

Posted: Thu Sep 06, 2007 9:56 am
by steve crawford
I think 25mph is no problem. With the bolt -ons you can do to these 650's.
Intake grates-impellers-bigger carbs-high compresion heads-exhaust.
A lot of guys on that can answer all kinds of questions.

For cross referencing Kawasaki parts to see what will interchange go to ... EHICLE.ASP

I found the same drive shaft is used from 1989-1999 on 650-750-900 2person skis. But the 650 stand up also has the same spline and I think the 550SX does also .

The 550 js does not .And if I had it to do over again I wouldn't get another 550 especialy the js. The splines don't match up with annything. So if you want a shorter drive shaft you are out of luck.

And the 550sx pump impeller is about 1/4'' bigger in dia. than the older JS
so watch out when geting parts. They started making the 550 sx in 89 or 90.

And the seado jet pumps have a plastic or teflon wear ring in the pump housing. Unlike the stainless steel other manuf. use.

Posted: Thu Sep 06, 2007 3:56 pm
by chappo1970
25 MPH should be very achievable in that size craft. Go with Steve's advice and research as much as possible before your build.