300/440/550 550sx Hull Modernization Build

Joined
Oct 20, 2011
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80127
subscribed....this is a sick build, i've never seen anyone do anything like this to a sx or js hull
I don't blame them! There's plenty of superjet's out there lol!

A few more little touches today. Hopefully I'll be putting a coat of primer on it this weekend, possibly painting?

The airbox/flame arrestor turned out pretty well! I took it out of the "molds" and cut it roughly to shape, as far as the lips are concerned.




-I'll be adding a top downward scoop on the inlet side, sorta like OEM F/A's are on single carb units.

Decided to just pull the trigger on the pump tunnel fill mod, or whatever you want to call it!

The I.D. of the OEM driveshaft connection tube is right around 1.45". I didn't feel like going out and buying anything cause I'm lazy and my Jew senses are in overdrive at this point in the build, so I decided I would make my own extension out of what I had - 1.25" PVC! The OD of this material is ~1.65" so I had to remove some, well a lot if it were to be sanded off. That just wouldn't do!

I present to you, the hill billy hand lathe!


Using a wood chisel, a clamped drill, a high tech drill trigger depressor, and a nice starret mic I was able to whittle down the PVC to the OD I wanted - ~1.45"!

If it fits, you must acquit! a.k.a. throw some peanut-o-sil on it and jam 'er home!



-Got 'er in all nice and deep like, but hows the inside look?


-Nice. Once this extension cures, I'll trim it to length and shape, then pack in the big void remaining on top (bottom) with body filler. From there I'll seal it all with a single sheet of resin rich 18oz 2X cloth so that water doesnt get in and saturate the body filler.

And lastly, some possibly unneeded, but always necessary reinforcement. I just wanted to tie the new nose section into the frankenstein lower front section. I built up a :):):):) load of cab-o-sil underneath portions I was planning on body blending between the old and new.


-Ski is upside down in this pic!
 
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Joined
Oct 20, 2011
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31
Location
80127
Don't wanna jinx myself...

But I think I just finished glassing??!?? As of now, the answer is yes, after I sober up tomorrow, that may change, but time to celebrate!!!

Pump tunnel fill mod - body filler sanded and 1 sheet of resin rich 18oz glass over it to seal and provide some structural barrier


From the top - you can see how "smooth" it is. it's not gonna win any 52mph racer's wet dream sanding contests, but it's pretty nice and smooth!



Put in some new mounts for the front of the gas tank, and they also work for the waterbox. These are about 1/2" structural fiberglass sheet. I'm going to weld up stainess brackets that will mount to these since the OEM's are different style and won't work on this flat mount
 
Joined
Oct 20, 2011
Likes
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Location
80127
Surf front foot hold concept

Well I got to ride a few different front foot holds and straps and call me crazy but I think this combines the best aspects of them. I'm a right foot forward surf stance rider when it comes to skis, but I definitely snowboard left foot forward. I think it just comes from my right foot being my "chocolate" foot (do they even call it that anymore? lol) for biking which I've done since forever.

This would be a part that would consist of a fiberglass core, then padded and turfed over.

Here it is right foot forward straight


Right foot forward cocked


Left foot forward cocked


I don't have it super firm as it sits for mock up, but it is pretty snug and feels awesome in any position. Once fabricated I will simply "bolt" it down onto the top of the gunwales (I wont be painting the tray, so when it gets back from paint, I'll be epoxying a reinforcing strip along the top to screw into) and it can be adjusted linearly forward or aft - something that no other front foothold does, and something that seems to be beneficial once you get better at surf riding (moving the COG rearward).

I'll mainly be laying up a flat rail with some curvature to add strength. All the contouring for ergo will be accomplished by shaving the 26mm plush under padding I have, which I'll be adhering to the bottom side of it.

Comments? Critique? Crazyness???

- IMHO this is the simplest universally adjustable design I can think of. It will be an easy glass lay up (light weight too!), and make for something that I can adjust if it's "not quite right" instead of the tedious process involved with foot straps, or the non existent adjustment of molded in front foot holds that place your front foot at the extreme front of the tray with no other options.
 
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Joined
Jul 30, 2012
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1
Location
valley springs
damn! ski is sickest 550 out there!!! i wish i could do something like that to my old skis. me and my cousin shoule bestarting a sn build soon, but skis mst be expesnsive where you live, i have a 1996 superjet with absolutely everything on it and im only 1800 into it with a fresh rebuild. but im definately jeaous of this ski and your talent! i cant wait too see future builds :)
 
Joined
Jun 14, 2010
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Location
NC
Well I got to ride a few different front foot holds and straps and call me crazy but I think this combines the best aspects of them. I'm a right foot forward surf stance rider when it comes to skis, but I definitely snowboard left foot forward. I think it just comes from my right foot being my "chocolate" foot (do they even call it that anymore? lol) for biking which I've done since forever.

.
I ride the same way right foot forward but snowboard left foot forward which is weird. you got a nice design for the front foot hold.
 
Joined
Oct 20, 2011
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Location
80127
Moar Sanding.... lots and lots more!

Well I have the hull at the shop were I'm going to paint it now - I've spent the last two nights after work sanding it and it can easily take 2 to 3 more! I rounded out all the edges on the hood and it looks great! No pictures tho - sorry (it's not that interesting anyways, lots of fiberglass dust lol).

In other news - I've been riding my 440 a lot more lately - My mentality is any time spent on the water is good time! Don't matter if I have a 440 with 120 psi compression or a Dasa 1200 in a rickter lol.

Last weekend I had 2 main issues with the 440 that were game ender's - I was getting the :):):):) shocked out of my finger from my trigger throttle so bad it would put my arm to sleep, and the engine would cut out after hard landings and after a while, it just wouldn't run at all if it was in the water (but sure enough as soon as it was beached or on the trailer it would run like a champ... wtf?). So to hopefully alleviate these issues I made sure there was a very good ground from my battery, to the ebox, to the motor, and to the carb (which is the only thing connected to my throttle cable technically...), not to mention the ground line that's already there to the starter (0 AWG!) The new ground cable is 4AWG stranded with good terminals so hopefully I can enjoy a good ride day at Brigantine this weekend!

I pimped out my 440 a little and I'll just post some of my work here since I may end up doing similar things to my 550!

Installed a limiting rope -



Made my own custom lower bracket - I wanted it to be very flush, so I used 1/8" angle aluminum and cut and filed it to a shape that I wanted. I used 2 1" SS carriage bolts and nylock'd 'em on the inside. Up top is just a eye bolt, I just tied my rope since I like knots, and the handy side effect they have of being adjustable ;). I used a 24" rubber strap and kept the "S" hook on one end and bent it to tightly fit around my pole pivot bolt. The other end has a locking loop which slides nicely on my rope.



Also installed a foothold (in the process of it actually!) I ride goofy foot, and After having the 440 out last weekend in some 5-8 footers I decided to throw a strap on it since there's 5 footers predicted for the Brigantine beach bash. Figured having the ski connected to me albiet not much power behind it, would still be better than not!

Took a few stances averaged them out - moved it back an inch (Since I'm still a n00b I like to ride farther forward than I should!) and started by cutting out some turf rectangles


-I took my dremel and sanded the area in the rectangle holes rough to fresh hull. I then plotted and drilled the holes. My buddies use these inserts from McMaster (MCM# 92105A100) which is basically what Blowsion sells for a lot more.

To keep the threaded insert's threads clean, I sealed the tips of them with a tiny piece of duct tape. This ended up working well!



I then applied cab-o-sil to the holes and nearby area



And drove the inserts home!



I went over the inserts with a toothpick and just made sure there was a layer of cab-o-sil over the flange to give them a little something extra in terms of resisting pulling out.



I'll throw the foot strap on tomorrow - I got a Dakine Supremo so there's a lot of adjustment! I'll probably run it a little loose to start?

Probably going to install some homemade hood straps tomorrow! I have extra buckles from the supplies I bought for the 550 project, all I need is the nylon webbing which REI just so happens to sell! Lunch time trip tomarrow... That should about do it for this 440 then. One day it may be getting a 550sx engine, so it's gonna be pretty nice by then!
 
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Mark Gomez

is where the surf is
Joined
Dec 5, 2006
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121
Location
Fullerton, CA
holly crap... all im going to say is that as long as its a 550 reed motor and pump that stays in this thing im a absolutely stoked on this project. Ill say it again, I want to ride this in Daytona. Really bad
 
Joined
Oct 20, 2011
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31
Location
80127
Soooooo Close!!

There's a very good chance she'll be done painting by this week.

Unfortunately there's a guaranteed chance that I'll return to being a full time student next week - so that will definitely put a hamper on this project's progression. Basically I won't have this on the water by this year's end. If I do get it on the water it will be in a local river just to make sure it runs! If I get lucky I'll take it down to Florida with me for Daytona.

I wanted to make sure I got it done painting by this week because having that part done means at least I got the hull done this summer...

Here she is with the hull having 1 or 2 applications of bondo to smooth out the valleys after it had been rough sanded.





I'm only planning on bondo'ing the top deck, and the sides of the bottom deck. The belly of the bottom deck will be sanded fiberglass only just for strengths sake. When sliding onto the beach and running over shells and hypodermic needles I don't want the paint getting scratched and exposing porous bondo!!

On a side note - I finished up the 440 mods - foot strap and surf straps. Both were 100% awesome at Brigantine this past weekend! I landed on my side more than a few times and I'm glad the hood was held on tight! The foot strap was amazing - Being a goofy footed rider, I never got to ride a ski with a strap I liked cause everyone I know rides regular. I nailed the mounting point on the first try and it made controlling the ski 10 times easier! Unfortunately on the way home I had the loose end of a tie down bundled up in it - well the wind got to it and long story short - tire ran over strap and pulled the foot strap inserts clean out! lol just glad it did not pull the ski off the trailer!

Based on this - I may or may not go with that foot hold/strap bar idea a few posts up. The foot strap... well - it just works pretty damn good when it's mounted how I ride!

 
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Joined
Oct 20, 2011
Likes
31
Location
80127
I will be really interested to see how you make the foot holds. Did you buy the brackets from SKi clinic? Or are you fabbing them. I am guessing the latter.
I was thinking of buying the brackets but I have a few tweaks to the design and don't really need the adjustability forward and aft integrated into the bracket - it will be part of the foothold itself! Think of it as a hybrid BOB/Rickter design.

After being able to ride in the surf for the last two weekends tho I'm not too concerned about the holds lol.

did you make it to brigantine? i didnt see one 550/440 there.
Yep - I was there Sunday on my 440, didn't get to ride until later on around 1:30 though because my kill switch wires were shorting out due to salt water so I had to diagnose that and then just disconnect them lol.
 
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