300/440/550 Js550 to yamaha 701

Foximus

CFL Cheapass.
Location
Oviedo, Fl
For one, using yamaha mounts will be more work than its worth. Especially if your talking about using the stock bedplates. they are non symmetrical and really glassing new mounts in the hull would be a total PITA. Id recommend sticking with the 550 mounts, OR modify using sea doo 720 mounts if you plan on building a motor thats going to have some kick behind it.


As for the pump. There is pretty much NO good reason to switch to a 144 pump. I mean after all the swapping and cutting and glassing you will be doing, unless you are a pro I garuntee you will not have everything in perfect alignment. Using a yamaha mid shaft will just grenade every time if you arnt dead accurate with this kinda thing. Also, the pump cavity will be fairly large and force the floor to move to far up (in my opinion).

The kawi driveshaft needs (almost) no alignment to run fine. And there are tons of different length shafts available, that ALL use the same bearing and shaft splines, and are easily interchangable simply by sliding it out. Yamaha, you only have a small shaft selection, and they all have to be pressed in and out every time. I mean theres no debate in my mind on which setup to use. Especially since there are just as good upgrades like TBM and hooker impellers for the Kawi pumps now.


I think i covered it all....
 

Superjetter_95

Looking to the sky
Location
League city tx
well my main deal with this project is im trying to use what i have at hand and buy as little as possible for supplies. i just happen to have all yamaha parts. it may sound like a pointless project, but its something we've wanted to try. and even if we dont do it the easiest way, i figure its worth a try. Thanks for the info Foximus, if i get the funds ill look into doing it that way instead.
 

Foximus

CFL Cheapass.
Location
Oviedo, Fl
I know what your going through and trust me, its not worth the extra hassle. I had my squarenose laying around and I tried to use as MUCH as I could from it to keep costs down. But ultimately I was forced to go with kawi stuff for the driveline, and really I dont regret it for a single second. I honestly believe its a smarter and far better designed system, other than the fact that its 4mm smaller in diameter.


Its actually pretty cheap too... And, an almost free trim setup... $20 for a x2 trim nozzle and your set. cant do that with a yama setup...
 

Superjetter_95

Looking to the sky
Location
League city tx
yeah i can understand the difficulty of things if i used the yamaha parts. Ill try to get a hold of a 650 pump if its possible. But as this is just an extra ski with parts its not in any rush to get it done, so if we do decide to use the parts we have instead, we're gonna take all the time we need to get it 100% right and not f**k it up the first go round.

I dont need to finish it half a$$ed and have it take a dump on me, thats the last thing i need :splatt:

again, thank you for all the info fox. Its a big help
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
The solution here is pretty simple,we have a for sale section here,list Yami parts ,sell Yami parts, buy Kawi parts ,install Kawi parts.
 

Superjetter_95

Looking to the sky
Location
League city tx
that might be what i end up doing, but the parts we have are all spares to the other skis so im not sure that'll work out.

whatever happens, im sure i'll figure out some sort of strategy and plan for this thing :Banane09:
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
do whatever you need to in order to run the superior 144 pump and all yami stuff. youll be happier in the end..

Yes I would print the above quote out and tape it above your work area because on about the fifth straight day of cutting, grinding and glassing ,when you and your garage are covered in a thick layer of SMC dust you will need that for some inspiration.:woot:
 

Superjetter_95

Looking to the sky
Location
League city tx
oh believe me, ive had way worse when it comes to glassing.

Ive got a 90 Sj that we cut the nose off of, the gunwhales down, the hood down, and then made it look alot more like a Rn than a Sn. so im not worried about the fiberglassing.

Im more worried about everything lining up right and fitting in place.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
oh believe me, ive had way worse when it comes to glassing.

Ive got a 90 Sj that we cut the nose off of, the gunwhales down, the hood down, and then made it look alot more like a Rn than a Sn. so im not worried about the fiberglassing.

Im more worried about everything lining up right and fitting in place.

You are about to get into more glassing than you can possibly imagine to make this work,getting it to line up is not going to be a cakewalk either,thats where the glassing comes into play at.:dunno:
 

vitalikol

Jetski-Snowboard
Location
Pennington,NJ
I got a 650 pump somewhere in basement. it's not turning ,I think. Will check it out and let you know . Will give it to you , just pay shipping
 

Superjetter_95

Looking to the sky
Location
League city tx
no i realize its not the same, i understand that. We had to do the same when we did the 144 conversion on the Fx1. Though it wasnt as big of an undertaking as this will be. Im not saying i can even manage to do this the way im saying, this is all just me talking about my ideas of how to START the project. i know my way around fiberglass, and im sure with enough time and effort i can make this all work out. Im not expecting to just be able to throw a 144 and a 701 in here and be done with it. i know there is ALOT of work involved.

my process is just all trial and error. if it doesnt work, ill take time to re-think and try again till its 100 percent right.

and as for the 650 pump, let me know about that. I'd gladly take that for the price of shipping. i appreciate all the help guys
 
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Superjetter_95

Looking to the sky
Location
League city tx
so i spent the most part of the day cleaning out my old 440 hull to be messed with.

i pulled out my 144 pump as well, with the superjet driveshaft.

i mocked up the 144 with the pump cavity "as is" to get a basic idea of all that has to be changed. Im thinking im going to leave the pump sitting as far back as it is, to get more throw for steering. maybe move it slightly more forward. and im also thinking of raising the tray slightly to gain a little extra room for the ride plate to fit.

as for the sides of the pump area, im going to have to gain an extra inch at the least to make room for the steering cable and water inlets/outlets. the ride plate may have a slight dip in it and be lower than the rest of the ski but it wont be much of one to make that big of a difference. I dont plan on riding this ski in much of anything but surf, so i dont believe the change in height will make that big of a difference. the pump tunnel only needs to be widened slightly to line up with the 144 pump correctly as well.

so thats the plan as of right now. For those who think this is a waste of time, thats all good and dandy. ill be happy with my lightweight yamaha powered Js hull :woot:

who needs those lightweight hulls that people can hold over their heads? just get a Js!
 

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Superjetter_95

Looking to the sky
Location
League city tx
this project has been put back for a while, we've got the lonestar freeride coming up and way too many other skis to fix.

Its been cut into and there is a build thread somewhere, ill look that up a little later and post it on here.
 
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