300/440/550 550sx Hull Modernization Build

[Edwardsjr1]

Ever thought of something like this? Kinda pricey though but "unbreakable".

http://www.blowsion.com/products/327-nose-outlaw-js-model-replacement.aspx

 

[Mobile Chernobyl]

lol that is pretty cool. I'm trying to avoid going back to the stock look at this point, never knew they even made that though! I thought blowsion was only concerened with the 650sx and newer.

If I manage to do mine right it should be nearly unbreakable as well.

 

[Polish jet pilot]

great project! Miss my 550....

 

[N2 H2O]

Look for a supertrapp waterbox. They don't have the big loop in them.

 

[Mobile Chernobyl]

N2 - thanks! I don't have the budget at this point to buy a waterbox (unless its like $50) but I do have the aluminum and a tig welder! least I can do is use their design for inspiration

Day 10... a good one and a short one!

Started the rocker! definitely a bit nerve racking of a procedure to dive into, but at this point in the build... I'm just shootin' from the hip lol.

Preparing the patient for surgery

Making the first few cuts and using the patented paint mixer stick spacer technique!

And voila! We have rocker (2 - 3 inches of positive nose action!)

Top view

Side view (gives a good idea of the curve!)

To make things easier for myself during the glassing procedure, I removed the gas tank and waterbox mounts!

I also finished the bond rail prep for the gull wing rails to be added!

And some shots with the hood on

This bitch is gonna need some nose work!

 

[Mobile Chernobyl]

Day 11... finally laid some glass!

Well I was tired of being destructive so I decided to be constructive.

Started out the day making some final sanding to the rocker - when you do the 2" parallel slice technique it creates a sawtooth texture to the hull surface, as the one upstream moves away it's closer face becomes "higher" than the down stream's near face. Basically I got the 40grit 3" disc out and sanded a lot until it was relatively smooth.

Next I made some paper templates which I used to cut out all the fiberglass sheets. I decided to split up the bottom into 3 pieces so it wouldn't stretch too much on the concave faces and form air pockets.

I decided to go with 3 layers of 1708 to reinforce the now split apart nose. Hopefully this gives it some strength for those 6" water nose stabs.

I test fit the cut out's to make sure I didnt royally up the templated cut outs.

Like a glove!

So now I prepared the bottom for all the epoxy resin that would be layed into the cracks. Duct tape fit the bill

Then I mixed up a nice penut butter batch of 3:1 epoxy resin and cab-o-sil and spread it out, and got in all nice in deep like on those cracks. I stopped after it was pretty well covered cause I'd be painting a layer of epoxy resin over the whole thing anyways for the bottom of the mat, and the mat is flexible enough to fill any voids.

Finally started laying some glass! fun. I gave the center section an overlap of the two outer sections to help tie everything together (hopefully)

The first layer looked pretty good, Basically just used this method:

Paint on a layer of epoxy, lay glass, painted on a layer of epoxy over that, skweegied it until it became a solid translucent sheet, then moved on to the next part. for the 2nd and 3rd layers I would repeat exactly the same. after the 3rd layer I rolled the out of it and came up with this.

With the roller.. I was afraid I'd lose it to the cause after reading none to good of a story about salvaging them. Well I beat the game! After I finished rolling, I stored it in a bucket of acetone to soften up the resin. After 10-15 minutes of soaking I blasted it with my compressor (sits at about 145psi) and all the resin was removed leaving a fresh roller ready for tomorrow! Yea my friends call me Jewish.

Tomorrow I'm going to do the engine bay and foot hold area's left wall reinforcing - 2 layers of 1708 on each should be adequate? I'll do a 1" overlay 90deg part in the engine bay to tie the floor to the walls.

Hopefully I can keep this progress up! I want to be riding in june!

I'm also thinking of getting a shortened pump cone, anyone think pump nozzle boring is worth it on a 550sx? I'm just looking to get the most bottom end out of this little engine as possible for as little lol - I hate working on engines.

Oh yea forgot to add - this is the first time I've ever fiberglassed lol - how'd I do? Still getting a feel for this composite working stuff, but I like it! Always wanted to build a positive mold carbon fiber mountain bike!... just may do it one day.

 

[crazy4sand]

Nice build

 

[jMike]

Wow! looks very interesting.

 

[iangdesign]

This is def an interesting build! Good work!

 

[special fx]

Cool project

 

[Mobile Chernobyl]

Got the engine bay walls traced out and cut out tonight - They fit pretty well I'd say! Too tired to try and epoxy anything tonight.

Going with 2 layers of 1708 with a little strip to tie the walls to the floor. Most likely overkill, but it's what I planned on originally so I'm stickin with it lol.

Also finalized the rear tray wall's shape - will have more on them tomarrow or later in the week. They needed some thought put into them for ergonomics and to help with the adjustable foothold placement.

 

[xpmr5]

Damn, this is an awesome build. Definitely try to get a bored pump nozzle and wet wolf pump cone. Those give it a better bottom end hit.

 

[Mobile Chernobyl]

Damn, this is an awesome build. Definitely try to get a bored pump nozzle and wet wolf pump cone. Those give it a better bottom end hit.

I was thinking about a pump cone - I saw the JRE on ebay for a good price. Noticable difference? I'm trying only to do modifications to the engine/drivetrain that will be relatively noticable! But I would definatly like to give this thing all the bottom end possible without going total loss, and I think I'll also have the nozzle bored because the nozzle bore/cone combo seems to be one of the best bangs for the buck!

 

[Mobile Chernobyl]

MOAR progress...

Well finally finished the engine bay reinforcement today. Also got the adjustable foothold structure piece in.

Engine bay shots

Basically did 2 layers of 1708 in the engine bay - the JS's are rather thin walled compared to other ski's, using my ultrasonic echo locator technique called knocking on the side of the jet ski with a fist - I was able to determine this.
I also put a 2" overlap strip on each layer that joins the front section of the vertical to the floor. Should make it good for hucking Niagara Falls, my ultimate goal.

And I got that 3/8" fiber board cut to match the new shape of the gunwales - a modern look. I played around A LOT, figuring out the minimalistic approach to sizing these support blocks - I'm going to have a 3 position horizontal foothold system, 1.5" forward and backward of what I'm pretty sure is "normal" riding stance. I made sure I included this adjustability for future mods (such as a big ass engine) and the fact that I cut appx. 2" off the back of the ski. They are also just high enough to accommodate a big ass foot, given that I have a angled drop floor at the footholds, with appx 1.25" of padding, and the footholds themselves are included in the measurement, so given I did my math right, these should have the foothold just barely hang out the back of the gunwales on the rear most setting (only the padding portion of the foothold will hang out, not the stainless steel sub-frame).

This material is pretty ing strong! It's also very dense, so I really didn't want to add more than was needed. To adhere them to the walls I first roughed up the surface, which was not easy by any means, like I said, these are basically steel - in fiberglass form! I then mixed up a peanut butter mix of epoxy/cab-o-sil and lathered a full serving on each, then clamped the out of it to the existing wall. I used all the peanut butter that oozed out to blend the transition from the support to the lower deck wall, and all other transitions present, including sealing up any gaps between it and the areas that didnt have a wall.

I'm going to apply a single layer of 1708 for the whole rear walls, gunwales included. I'll also throw another layer just on the back half to add more support to these bad boys. Can't be having my walls snap on me! like I said, hucking Niagara falls.

Here's how she sits after day 13

I may or may not be buying a Kawi 750ss as a donor ski for the engine and pump... Hopefully I can find one cheaply (got to call the guy tomorrow)! I'm really getting the itch to go all out lol.

 

[Mobile Chernobyl]

Got a little more work done today, nothing major.

I templated and cut out my reinforcement for the tray walls.

I'm gonna do one 1708 across the whole wall, and an additional along the rear half to give the adjustable foothold's some extra strength.

I was looking at the chine's on the hull

And I decided I'm going to do a taper from front to back with increasing chine depth - in addition to a slight hull truing. I'll probably start this when I do my widened bond rails - which will be after the tubbies which will be after the hood and nose are done - lots of work left!

The deal for the 750 didn't pan out, and quite frankly, I don't want anymore work now, I'm ready to ride! And I don't remember this engine being too sluggish as it is, perhaps a pump cone and nozzle boring will give it a little extra snap, maybe not, but it sure will be cheaper than a whole 750 swap! If anyone has any other recommendations for monstrous bottom end from this tiny engine let me know! Hull handling is first though, without a nice hull, all the power in the world is not usable, which I would think would only be amplified by how "bad" the stock 440/550 hull handles lol...

 

[motoman96]

Mucho respect for that much work on a 550. Looks good an my hat goes off to you. Everyone, myself included will say get a superjet, but I like your determination. Nice work, looks good so far.

 

[xpmr5]

Id throw a high compression head on it, lightened flywheel, sbn44, bored nozzle, pump cone, factory halfpipe, and flow control valve, and call it a day.

 

[Mobile Chernobyl]

Id throw a high compression head on it, lightened flywheel, sbn44, bored nozzle, pump cone, factory halfpipe, and flow control valve, and call it a day.

Well of them I'm just sending out my head to get milled and nozzle to get taper bored. I'm getting a JRE stubby cone, and already have the lightened flywheel and factory half pipe. My current carb setup is a set of SBN 38's - should be adequate no? Mathematically speaking, they have more surface area than a single 44, but I've heard a single big carb is usually better for bottom end.

This flow control valve you speak of - got any more info regarding a 550sx setup?

That's about all I'm gonna do lol - I don't want to dump too much money into this, I do want it to be very fun for a 550sx though! I do realize that there is no making this into a superjet, and that a superjet would have been a better investment probably, but I'm enjoying all this work, and I get to make exactly what I want, how I want it - which coming from a future engineer, means a lot lol.

 

[Mobile Chernobyl]

Mini update...

Got the gunwales glassed.

I'll know by tomorrow if this will be strong enough!

To the more knowledgeable out there:

Since I've already mega reinforced my hull walls - would I be okay with coating my tubbies made from carved extruded polystyrene sheets in two layers of 18oz e-glass cloth? I'm not looking to add much more weight to this hull, and since I've already reinforced it internally - would 2 layers of 18oz eglass mesh be adequate to provide enough strength for normal wear and tear of the tubbies if they are build up with polystyrene sheets?

Just wanna make sure! I have 6 yards of 18 and 10oz eglass - probably not the best order thinking back on it now, but it may provide some use!

 

[xpmr5]

Flow control valve cuts off water to the stinger of the pipe at low rpms to improve throttle response at lower rpms. It dries out the waterbox.

Which brings me to my next question, what waterbox do you plan on using? If you're on a budget, you could gut a stock waterbox for free minus some sealant to put it back together. Also, many aftermarket boxes can be had for $40 to $50 shipped. I run a mariner on mine, lots of people say that other brands are too loud.

Another thing that I consider an absolute must on a 550sx is an ocean pro steering nozzle. It makes the skis steering so much more responsive. Intake grate and ride plate is personal preference really. if you're looking for a freestyle setup, you might want to consider a toploader to keep the ski hooked up in chop and surf and increase the water flow to the pump when jumping from wave to wave. R&D makes the most aggressive grate for the js hull, but will need some epoxy or glass reinforcement on the front intake inserts to assure that they do not pull out from the hull. I run an ocean pro skegged on mine, but you might be better off with a stocker for freestyle to let that back end run free when hitting waves. Good luck!