FX-1 My mini mag fx1

[EfX]

Neat idea. Very interested as I have 2 old WR pumps with some sort of stainless props on each just sitting around for years. Subscribed.

 

[waxhead]

The jig is finished it will allow me to put the shaft on the new pump and have it sitting in the same place it was on the old pump. I can then make up new mounts for it and put it straight in.

 

[EfX]

Nice

 

[waxhead]

Do you think the setback pump slows the hull down when it comes to flicking it. I would have thought it made it quicker

 

[KTM434]

Setback referring to the stator section or the mounting location of the pump? If stator section I don't think it has any affect on steering, it just has more pump volume in front of the impeller.
if you're referring to how far the pump is mounted I think a further set back pump gives more steering leverage but doesn't make it steer quicker. If the pump sticks out because the hull is shortened then the hull has less surface area in the water which allows it to be more nimble and make you think the pump sticking out is why it steers so quickly. If the pump is moved back on a full length hull I think it'll still help with leverage but will make it less nimble (increase the turning radius kinda like increasing the wheelbase on a car or stretching the swing arm on a motorcycle). Having the pump/steering nozzle closer to the middle of the ski will definitely make it turn quicker and make the pivot point closer to the middle/front of the ski. I chopped and rockered a Blaster and loved how nimble it was being so much shorter. My plan for my next B1 was to shorten it and move the pump forward and set it up to run a SJ driveshaft so I could have my steering pivot further forward on the ski to be more nimble if that makes sense? I have a feeling that's what you were referring to about not liking the 144 pump swapped FX1s you rode...

 

[VXSXH20]

I'd think it would make it more responsive and twitchy as the thrust nozzle is further back and shifts the control of the back of the hull more so than stock..look at all the am freestyle hulls and newer sj...same principle I don't think it slows the ski down as much.. Maybe the setback fx1 you rode had a few kinks to be worked out like optimal impeller pitch and slight cavitation, ride plate etc etc..?

 

[KTM434]

AM hulls don't have the pump moved back, the hull is shortened like I mentioned. They still use SJ driveshaft and midshaft so they didn't actually move the pump back or lengthen the driveline, it just looks that way. I bet if you shortened the driveshaft just as much as you shortened the hull your steering would be extremely quick. They don't do this on AM hulls since you'd need to move the pump intake further forward also which would have a negative affect on backflips since the intake would leave the water earlier and decrease the pump volume for maximum thrust while beginning your rotation

 

[waxhead]

Thanks guys was just wondering if I should do it, I can do anything pretty much at this stage as I have yet to turn up the liner

 

[VXSXH20]

KTM- You explained it much better than I ! :biggthumpup:

 

[waxhead]

Here is the new pump sitting on the jig with the fx1 driveshaft in it. I had to use different bearings as the wr500 uses a larger bearing. No issue it the same as a kdx crank bearing.

I have cut the rear tabs down and will make new ones and weld them on next week. then i can work out the length of the liner and start turning it up as well as making brackets to mount it on the old mounts

 

[special fx]

Running SJ shaft and setting the pump back a little will give you more steering authority and help load the pump better. It looks like you have very little room for the prop and liner with the FX shaft?

For ref, one of my FXs has the pump setback about 1" further back than my others and it feels like it has WAY more steering and is much more "flickable", even though they all have the same steering throw.

Are you keeping the water fitting on the bottom of the pump? Just wondering if ride plate clearance will be sufficient for that.

 

[waxhead]

Its a bit of an illusion it is 2mm less than a std fx1. I can machine the shaft if I like. I am running 12mm wide bearings to allow it to have the max room I can. I was thinking about setting it back but a superjet is 2" longer and I dont want to go that far back. If I could get a 25" shaft I would do it for sure.
I am not leaving the water fitting on the bottom its jsut that this is the way its done in the wr500 so the dowel hole it there I will drill another hole to line it up.
I will run it on the same side as a stock fx1 to make it easier to hook up the line

Thanks for the feedback i will look at maybe moving my pump back 1" somehow

 

[KTM434]

FX I agree that a setback pump will definitely give more pump volume if you leave the intake tunnel in the same spot and having your steering pivot moved back 2" will definitely give more steering leverage, no doubt. Do you think if you used the same 144 pump and didn't set it back 2" but you cut the hull 2" shorter that it wouldn't steer quicker than a stock length hull with pump mounted 2" back?

 

[waxhead]

Ok well still working away on this thing. I have been busy and so havent done as much as I wanted.
Here is one of the flanges cut out and checked on wood before I take it to the water jet cutter and get it cut out.
Whe have a cnc router but it will not cut stainless

 

[waxhead]

I got my metal plates back from the lazer cutter and now just need to cut the liner to size and get it welded up. From there I can bolt it on and make the front mounts.

 

[waxhead]

I cut the liner material the right length and will now get it tack welded and start to make the mounts

 

[CRJ]

if this gives a viable improvement id be interested in one. with the 1100 motor going in my LX, this is easier then glassing in a new pump and only 11mm smaller then the 144's

 

[River Rat]

Intense !

 

[waxhead]

It should be a lot better, its a bigger pump with the 75mm hub as well. I will let you know how it goes. NO glassing work just a bolt in is what I am trying to achieve.
This started out as the same pump as your lx by the way. So in reality it would be easier as it does not have to have the back mounts made

 

[CRJ]

awesome! let me know! im picking up the parts slowly and im sure ill overpower my pump.