300/440/550 550 to 750 Motor swap Rumor

[dbrutherford]

I am curious why you put the fitting on the back of the head pipe?

I was just going to run a second hose off of the head to rid the exhaust of the extra water. Then I was goingto have the head pipe hole welded up and have a FPP water adjustment screw added to that spot.

I do like how you put the larger 3/8" line and fitting where the stock bypass line is.

I also wanted to weld the the two cones together to eliminate the center coupler.


NICE LOOKING SKI!

DBR

 

[Mark Gomez]

this is the first 550/650 i built. started out running a westcoast pipe, but they are crap. went to a modified stock 650 with a long cone.

on my current conv ski i'm running a factory pipe, sx pump, 19 prop,ported cases and cylinder, 205 lbs comp, aluminum flywheel and more.

heres a pic of the first one with the modded sx pipe.

wow that looks great! Nice build! how does the bottom end perform on it?

 

[sjaholic]

this is the 550/650 that i currently have. it will be going up for sale on a couple of these sites by the end of the week.

i think i used alittle too much light on these pis.

 

[dbrutherford]

Is that capped off fitting on your head pipe for water injection?

DBR

 

[sjaholic]

dbr, yes it is. i never used it. here's some more pics. this ski is listed on pwc for sale: 1987 550/650 conversion ski

 

[Mark Gomez]

Holy CRAP!

HOLY ********!:shocked: :shocked: :bigeyes2: :eek2: that thing has to RIP IT UP! you have never used it!? what are you selling it for like i could ever afford it. just curious and how you got that factory pipe in there is beyond me. wow Great ski :bling:

 

[Big Kahuna]

there is a conversion plate on ebay right now.

 

[Mark Gomez]

yeah i know its like 60-90 bucks or something

 

[dbrutherford]

You can get on on ebay from Freshwatercraft. I swear I think the guy must have a CNC mill or someone making parts for him because I have never heard of Jet Race Engineering and he is always selling parts under that name. I think he just bought a big stock of aluminum and had someone start milling him out parts to sell. Maybe I am wrong?

Also look at Samora's Ski Performance and jetSkiMechanic. Both of those guys machine them too. But if they are new.. you pay new price....

 

[sjaholic]

fearless i never used the water injection. i bought the hull a couple of years ago from crammit. ran a 650 motor i built in it for a summer. charles sold me this motor the next summer. time to sell and work on an fx1.

it's an awesome ski and it rips. pretty sure BK rode it when charles had it. matt

 

[Conquistador]

I'm considering putting a 650 or 750 into my 550 hull. If I put a 750 in, is it correct that I could use the 550 waterbox (I have a Factory Pipe one with one weekend on it-Daytona).

 

[dbrutherford]

Yeah you will use the 550 waterbox. Pipe and exhaust manifold will need to be a 650 Kawie of some type.

DBR

 

[Conquistador]

:biggthumpup:

 

[pjsrider]

I am just wondering why go through all the effort to put a 750 in a 550 hull? My pjs 550 can beat a seriously modded 750 out of the hole anyday and it just barely outruns me on topend. Wouldnt the 750 burn twice the gas for a negligible power gain? If you do go the 650 route then think about geting the 700cc conversion for it. It was made by pjs back in the day and replaces the 650 cylinders with one that is 700cc I believe. Might get you the extra power without haveing to go all the way to the 750.

Jay

 

[pjsrider]

this is the first 550/650 i built. started out running a westcoast pipe, but they are crap. went to a modified stock 650 with a long cone.

on my current conv ski i'm running a factory pipe, sx pump, 19 prop,ported cases and cylinder, 205 lbs comp, aluminum flywheel and more.

heres a pic of the first one with the modded sx pipe.

Is that a bearing sticking out of the front of the flywheel cover inthe second pic?

Jay

 

[Conquistador]

I am just wondering why go through all the effort to put a 750 in a 550 hull? My pjs 550 can beat a seriously modded 750 out of the hole anyday and it just barely outruns me on topend. Wouldnt the 750 burn twice the gas for a negligible power gain? If you do go the 650 route then think about geting the 700cc conversion for it. It was made by pjs back in the day and replaces the 650 cylinders with one that is 700cc I believe. Might get you the extra power without haveing to go all the way to the 750.

Jay

Because my 550 motor is toast & I can get a running 750 (needs stator) for $150. I plan on getting another oversized gas tank. (ruined the first one while trying to get a 550 1/2 pipe to fit in :frown: )

I'm just thinking that installing a 650 motor may be a little easier. Plus, if I get a good deal on a 650 I'm checking out tomorrow, I may use the 750 as a ski for my dad to ride. (it's in a Kawi SS)

 

[Conquistador]

dbr, yes it is. i never used it. here's some more pics. this ski is listed on pwc for sale: 1987 550/650 conversion ski

Are those Wedges in that 2nd pic. Do you like them? I may do that instead of footholds or straps.onder:

 

[ang4th]

http://cgi.ebay.com/ebaymotors/ws/e...ORE:PROMOBOX:CUST&viewitem=&item=230107354516

 

[Conquistador]

Good looking out!:woot:

 

[Conquistador]

Yes, it can be done, I have done several. But as always it's more complicated than what was told you. I'st thing is the need for a jetcraft engineering bed plate converter, This is so a 750 motor will sit on the 550 bed pan. then the couplers come into play. You will need to adapt the 750 ingition box into the 550 hull. The pump will also need to be modified. The easiest is to install a 550 sx drive line (91-94) If the earlier model is used, you will need to have a thru hull support installed. those were made by either PJS or westcoast. The final piece of the puzzle is the exhaust. You will need to adapt a k650 exhaust to work on the 750. again the PJS or westcoast will work best. But expect to have cutting & welding as part of the install. All in all a fun project........
Little boats like that are crazy fun rideing at the speeds achivable, with that motor.....

ski ya, Paul

What is required to get the 750 electrics into the 550. Can the electrics of a 750 box be put into the 550 box?