Superchicken 750 pump swap

[James.Ruby]

Is this a fairly straight forward swap? Based on what Ive gathered, I'll be modifying and installing a 750 pump shoe, and then the rest will be a bolt in affair?

The previous owner trashed the 650 pump so I'll either be ordering the parts for the conversion, or replacing the 650 pump.

 

[fastgtfairlane]

You'll probably have to do some clearancing to the hull to get the shoe to fit. Pump should bolt up otherwise. And you'll want to double check your driveshaft is the correct length.

 

[special fx]

That’s a lot of work for no performance gain, what’s the rationale?

 

[fastgtfairlane]

Only benefit i could see is more impeller choice and not having to seal the shoe everytime you swap impellers. But once you get the impeller right there's no need to swap it.

 

[Myself]

They are both 140mm AND the same design. Silly to go through a swap.

 

[kevbo]

The last time I had a 650 upside down for a 750 pump swap, I put the 650 unit back in and just modified 750 impellers. The swap was looking to be a lot pain for no gain. Mainly because the 750 pump shoe doesn’t fit.

 

[Myself]

The last time I had a 650 upside down for a 750 pump swap, I put the 650 unit back in and just modified 750 impellers. The swap was looking to be a lot pain for no gain.

I have also modifed 750 impellers. In fact a stock cutback SXR800 impeller works GREAT in a 650 Jetmate!!

 

[fastgtfairlane]

Another friend is using a oem sxr impeller in his x2 behind a 61x and it runs excellent. Also 650 pump.

 

[kevbo]

I’m using a solas 11-16 concord on a “limited” 650sx. It turns 6600rpm and goes 42mph. Best low speed acceleration I ever got out of 650s.

 

[WFO Speedracer]

I did the swap on the Thunderjet because I was still at that stage where I could and it was now or never , but yeah for most guys it's not worth the hassle for sure .

 

[James.Ruby]

Reason behind considering the swap is my 650 pump is trashed from the previous owner. They ovaled the holes for reasons I haven’t figured out yet. I just got done painting the bottom so if there’s any hull mods that need done I won’t bother with it for no gains.

it will be getting a 750BP with a Coffman pipe. I’m not very well versed in the kawi world so I appreciate any and all insight.

Here’s a couple photos of its current state. I’ll most likely make a build thread once it gets a little farther along. Progress is slow in between other projects and work.

 

[WFO Speedracer]

I realize it says X2 PUMP SWAP , other than what to do with the intake grate the procedure is the same . There is also some stuff on my Thunderjet build page here starting about post #215 . Just so you can kinda see what is involved .

https://www.pwctoday.com/forum/technical-discussion/vintage-skis/kawasaki-x2/241464-my-x2-750-pump-

Thunderstruck ! Counter to the Blunderjet thread

I laid up two layers on both sides and pulled a tie down strap across it , we will see what happens tomorrow.. I will go back and clean up those epoxy drips in a few minutes , right now it's lunchtime.

www.x-h2o.com

 

[James.Ruby]

I realize it says X2 PUMP SWAP , other than what to do with the intake grate the procedure is the same . There is also some stuff on my Thunderjet build page here starting about post #215 . Just so you can kinda see what is involved .

https://www.pwctoday.com/forum/technical-discussion/vintage-skis/kawasaki-x2/241464-my-x2-750-pump-

Thunderstruck ! Counter to the Blunderjet thread

I laid up two layers on both sides and pulled a tie down strap across it , we will see what happens tomorrow.. I will go back and clean up those epoxy drips in a few minutes , right now it's lunchtime.

www.x-h2o.com

Thank you, I’ll take a look when I get home from work and see if it’s worth the headache but from what most of you guys have said, it’ll be simpler to put a clean 650 pump back in it

 

[kevbo]

A high port 750 will need a low pitched impeller. The stock 650 nozzle will also make the most thrust. Leave the engine stock, especially its head and ignition. It is very easy to melt a piston on these with an aftermarket pipe. And, as always, open the top carb screws enough to stay a little rich of peak power.

 

[James.Ruby]

Thank you, my next questions were going to be prop recommendations. Interesting leaving the stock head on it. Without knowing better I figured a head would accompany the pipe but I’d rather reliability over peak power. I was going to send the electronics out to get refurbished but leave them stock.

 

[kevbo]

The ignition boxes are big pin specific. They should be marked 3735, 3738, or higher. Small pin boxes are 3728-3734. Do not use these in any high power engine, they have no retard curve. There is a one year 750zxi cdi box that is battery powered as well as most used on 800 stand ups. The stator will have two poles with no wire if it was for battery ignitions . The last high port 750 X2 I assembled needed the solas small hub 11-16 in order to get on the pipe quickly. Any solas large hub will need to be pitched down a lot for a high port cylinder. Low port cylinders can pull more impeller.