The Little Prince (1984 JS440)

[mrfist9]

She's a runner!

Buttoned up ready for a test day!

Got the impeller shimmed properly.... It was way off. Cleaned up some of the electronics hopefully with the way cleaner looking flywheel & stator, also suspected the CDI/COIL so swapped them out. Praying my battery drain & weird plug nuking issues will be resolved.

 

[mrfist9]

So rode this
Maiden voyage with the 650 in it.
Did awesome, felt good with the 16.5 skat & 550 pump.



Got it home, plugs a bit dark. I had an issue with this motor set in my other 440 murdering plugs despite running great... this honestly runs better I didn't notice any running issues tune wise.. only thing it did weird was kinda bog down when I let it idle on the trailer for 20-30 seconds. You couldn't dream of convincing me it's an electronic issue I replaced literally everything.

Currently on the SBN44
140
120
2.0 N/S
95g

So I'm just lean out the screws and see what I get next outing.
Shot in the dark but kinda speculating maybe the Seadoo box isn't the best at evacuating water it definitely kinda loaded up at idle so tossed in a JW valve.



Wax racing front fill came in! It sat far enough forward to hit my waterbox, so I trimmed the front tank fitting down a bit, heated it up and reshaped the hose bead with a 2x4.

 

[mrfist9]

Rode this Saturday. Absolutely impeccable. It is just way to fun to do tailstands, got it up to 44 mph.. it's got more in it pussied out, maybe the ocean pro ride plate but it is just dying to death roll at speed lol. I can do a tailstand on this thing likely long enough to fry my lungs. Such a good ski.

Don't think I ever tried leaning it out, was super short on time. I'm hoping it's just too fat on the top end, it's not really excessive in any manor regarding load. Skat 16.5. Plugs were piiiitch black, but response is genuinely a 10/10 it is smooth 100% of the time. Idle, transition, midrange, it all feels absolutely fantastic.

 

[Myself]

I have also noticed mid 40's is where these things start to "roll". I've learned on mine to keep putting weight on the left as I increase speed. Just don't forget to balance out before letting off the throttle, otherwise the ski 'unwinds' and piches you off the left side!........still puts big smiles on my face though. Does the rear of yours also skate around like you're riding on marbles??

 

[mrfist9]

I have also noticed mid 40's is where these things start to "roll". I've learned on mine to keep putting weight on the left as I increase speed. Just don't forget to balance out before letting off the throttle, otherwise the ski 'unwinds' and piches you off the left side!........still puts big smiles on my face though. Does the rear of yours also skate around like you're riding on marbles??

It's certainly one of those things once you lose the confidence in it and start thinking about the roll you're better off backing out. Have to put your blinders on for sure.

Marbles is a great way to describe it, basically any steering input is worthless in a handling kinda way I find on a 440/550. They only seem to properly turn when you dump them on their side. I definitely find myself primarily just kinda pointing and shooting wherever I go with them A>B

So much fun to just be rowdy on, slides, tail stands, spins, anything of the sort

 

[Myself]

When I have mine wide open (upper 40's) you constantly have to 'adjust' body positioning to stay on the throttle. You can literally watch the nose hunt back and forth while you're still going straight. I'd love for somebody to get some good footage and just see exactly HOW MUCH of the hull is actually still in the water LOL!!

 

[mikidymac]

16.5 seems pretty low on that. I am running a bone stock Yamaha 650 in my 1991 440 hull with a 550 pump and a straight pitch Skat 19 is perfect.

 

[mrfist9]

16.5 seems pretty low on that. I am running a bone stock Yamaha 650 in my 1991 440 hull with a 550 pump and a straight pitch Skat 19 is perfect.

it definitely is I have my eyes out for something 17+ Not the easiest thing to come by at a appetizing price

 

[mikidymac]

I just had Impros repitch an clean up an old one we had laying around.

 

[mrfist9]

Been riding this thing all summer. Absolutely love it. Ended up with some slightly different jetting.

Tried a ton of different ride plates.

Now testing out some fishstix!

This next outing is my first time out with a skat 18p, took forget to get ahold of one.

 

[E350]

The FishStix look cool!

If you want to try a slightly more expensive version, Wax has these which I put on my FX-1 and everyone and I mean everyone likes how they improve carving and reduce sliding -- when you want to slide you simply do not lean the tail of the ski as much :

Adjustable Billet Sponsons

Why slide? Carve like the pros! Introducing the Wax Racing Products Billet 6061 Anodized Buoy Shredder Adjustable Sponsons. Forget about re-drilling your hull to fine-tune your ride. With our buoy shredders, you simply unbolt the blades, loosen the body, and adjust them up to 100mm in each...

www.waxracingproducts.com

When I finish re-carbing my 550sx I will likely add them to it as well.

Here's the violet color on the FX-1:



And never forget Jeff Jacobs advice on how to build a fast 550:

SPOTLIGHT: Jeff Jacobs

Motor Action Media interviews the greatest stand up Jet Ski racer of all time, the legendary “Jammin’ Jeff Jacobs, a ten-time World Champion.

motoractionmedia.com

 

[mrfist9]

So after an entire season just giving this ski hell.




It finally conked out at SFF.

ZERO spark.

Tried all the basic stuff, unplug the killswitch, even went as far as to swap out the cdi for another I had, figuring it could only really be that or the stator.
Nothing; womp
So started taking it apart trying to figure it out, been going crazy with the DMM, stator passes resistance test... also looks goregeous.






I want to try again a cranking AC voltage test... pretty sure it passed when I did it at the freeride but I wanna verify before I truly believe its not the stator. I unfortunately don't have one laying around to compare against.
Also speculating could be something stupid like the stoprelay, so some more stuff to try.

hit me up if you have a 650 stator!

 

[WFO Speedracer]

You are looking for around 30-35 VAC at cranking speed, anything less than that no fire , on the stop relay you can just take it out of the circuit , it will still cut off when you hit the stop button but you have to hold the stop button till the engine stops spinning , the stop relay provides instant stop when you hit the button.

If you have 35 VAC when cranking the issue is obviously something upstream, the CDI -COIL is the most common failure point in those systems , although a lot of times it's just the coil wires that are bad, they are notorious for internal brakeage.

I did one on a TS one time that had at least 20 breaks in a section of wire about a foot long , I actually cut the wire open with a razor blade to have a look at it , that one still ran but gradually got slower and slower till it would completely cut off .

 

[mrfist9]

So. Did some wrenching finally. Got another stator in the mail. Looks worse then the one in the ski.

Wanted to compare cranking VAC between the two. Probably pulled the flywheel 4-5x today. Both did the same. 25-35ish VAC. Playing with it a bit I noticed that it has just the FAINTEST bit of spark with the new CDI in there. Gonna stick with the original stator.

Stared at the weak spark for a bit. Grabbed the old CDI and plugged it in. ZERO spark. So.. maybe it was CDI all along and my replacement was still bunk.

I said enough was enough. 650 CDI time. Tested it out. Best spark I've seen yet we'll give it a go.

As I'm looking at this mess I just feel stupid for trying to continue with the 550 CDI. Why does every 650/750 swap goober suggest these antiques are a good idea is beyond me.



Didn't take too much to fit it in the stock ebox, cut the post the stop relay sits on and horribly cut back the other. Shout-out to the Milwaukee Dremel.



Spaced it up a little to clear the bottom and some room to tuck the wires. Filed down the edge of the cdi a bit to fit as well.



Have some reassembly to do but optimistic!

 

[WFO Speedracer]

Yeah the 550 CDI was never a good idea but like most things someone tried it , it worked and everyone jumped on the bandwagon, mismatching parts like that is never a good idea.