What you need to buy to put a 650sx into a 550 hull HELP.

streetking-15 · May 5, 2014

So Im new to the conversion idea of going from a 550 engine to a 650sx engine. if anyone out there has had experience with this, which ive seen a couple... would you guys be able to help me assemble a parts list of things to get and what i need to replace? if so I will definitely do a photo thread of the entire conversion. ive already disassembled the ski on this thread.

http://www.x-h2o.com/index.php?threads/1986-js-550-first-rebuild-thread.146359/

streetking-15 · May 5, 2014

I know that Im going to need this engine mounting plate. if anyone has one already and has dimensions Im thinking of just making my own, but i know you can buy it online for $100.

http://www.ebay.com/itm/330767689707?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

silverbullet · May 5, 2014

I highly recommend that you get the plate, the amount of time you'd spend trying to fab it yourself is worth the cost.. I have mounted a 750 in a ljp hull using the plate I got from rcjs/watcon.. I could've made my own plate in a friends machine shop but for the 90$ I spent I would've spent more then a couple of hours doing it.. I still had to dremel down the heads of the bolts I used to clear the 550 plate, and then you simply use a set of 550 plate to case bolts to mount the bed pan to the adapter plate.. depending on what pump/prop you have now, you may have to pitch up to handle the bigger motor..

streetking-15 · May 5, 2014

Okay thank you for the info! Anything on upgrading electronics or the pump? And what about the carb?

silverbullet · May 5, 2014

Well your gonna have to fab and mount an e-box for whatever motor your running, if it's a 650, then an e-box from like a 650sx.. carb.. well that depends on just what parts your going to use, and if any mods or pipe is added.. pump should be clean and fresh and will more then likely need to be slightly higher pitch then what you have in there now, and again that depends on the mods added to the motor.. what year 550 pump/hull is it?? 440/550 pumps can handle a limited amount of hp increase to an extent without cavitation..

streetking-15 · May 5, 2014

I have a bunch of photos of the ski on my other thread that I mentioned. And it's got a stainless aftermarket prop but I have no idea what the pitch is.

silverbullet · May 5, 2014

Well your gonna have figure it out..lol don't get me wrong, it will work with what you have.. but will it be to full potential? Will it cavitate? What year is it? 82/89? Original pump? I'm guessing it's that age range cuz you have a piston port motor..

streetking-15 · May 5, 2014

as far as i know its an original pump, and i would want to get it up and running before I change the prop. its an 84 according to the title but I feel that it is more like a 86 cause of the side port exhaust...

silverbullet · May 5, 2014

The last 2 digits on your vin plate will tell ya.. you can roll if over and inspect prop for I'd marks.. but if I was you, and your driveline being used and worn, I'd go thru the pump and driveline bearings, upgrade the prop to what you plan on for motor and mods, and build it the right way... otherwise it's like putting a big v-8 in a 4 cyl car and spinning the wheels and not going anywhere... the prop is where it's at on any ski..

streetking-15 · May 5, 2014

see it all is in pretty good condition compared to the motor when I pulled it so I have a feeling like the guy before me replaced it all already... its hard to tell though cause with almost every standup nobody has a track record for whats been done to it... but Ill definitely take your advice on the prop.

silverbullet · May 5, 2014

You can still figure out what ya got by looking the prop over.. and definitely look at the driveshaft housing seals for signs of grease leaking or you'll put it all together to just take it all back out again..

streetking-15 · May 5, 2014

i gotcha. and on the vin number, its scratched off the back of the ski and under the battery box, so maybe the vin on the title is correct but idk. and just to get a better scope on this project im planning to put a 650 in it but keep it as stock and reliable as possible.

b-rad · May 5, 2014

If your going to do a 650 you'll need to do some mods like silver bullet said you need to do a test fit with the new motor to see what your going to need to do for pipe ect.... It's not stock after your done but can be just as reliable

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