Custom/Hybrid My 760 SX (A 300 SX transformed from a SJ)

[Liquid Graffix]

Not a for sure on the stock pole just yet. I just noticed it sitting there so I set it up to see what it would look like. I still have an idea for an aluminum pole that I will more than likely end up doing. It will look similar to the "goose" pole. I'm still a ways away from that yet...

but thanx Scientist for the tip.

 

[tokarzl]

The engine looks real far back unless that is a backflip only boat its going to ride extremely nose high. what about using a longer drive shaft like a vxr when i mocked that up the motor mounts where on the front motor mounts of the 300 and the pump ended at the end of the hull leaving the exit nozzle way out. if that is to long you could also use a blaster drive shaft thats inbetween the sj and the vxr

 

[Liquid Graffix]

Ya I did think of that. I'm still messing with the placement so as soon as I decide where the pump will live, then I can see how far I need the mid shaft to come out. I do have a VXR drive shaft laying around...

I'll have to find out the length on a Blaster drive shaft for comparison.

I plan on having the gas tank as far forward as possible so that will help with the weight a little bit. I may end up only setting the pump back an inch or so and then just shorten the back of the hull another inch.

The 300SX hull is: 78.7" - (6.5 feet long)
A Superjet is: 88.2" - (7.35 feet long)

BOB gen 1 is: 78.5"
BOB gen 2 is also: 78.5 but it has a 3" set back pump

I'll do some more measuring tomorrow, but I think I'm going to aim to get the hull as close to 6' as I can.

 

[Liquid Graffix]

Did more cutting today and finally got the pump section to fit somewhat flush with the hull. I put a couple brackets on it just to hold it in place for now to be able to take a step back and see how it looks. I think I will shorten the pump section to just before the bolts for the nozzle. I have more trimming to do and I am going to cut out the top of the tray so I have access to glass in the pump section.

The rear of the pump section is going to stick up above the tray when it is glassed in so i will have to figure out something to do about that later.

It's coming along... slowly...

 

[Melmack]

LOL, one of those pics looked like a SJ humping a 300!

Looks good, how are you mounting the motor?

 

[Liquid Graffix]

LOL, one of those pics looked like a SJ humping a 300!

Looks good, how are you mounting the motor?

Still messing with that... I'm either going to make aluminum brackets that mount to the original 300 spots OR grind down the mounts in the 300 and glass in the mounts from the SN hull that I chopped up.

 

[Melmack]

Here's an Idea. Glass will vibrate loose. Have you messed with polyurethane adhesive? I've used a ton lately. It's amazingly strong and used for skis all the time. I noticed that not only is it used everywhere but the FX-1 came from the factory with mounts from another ski glued into the hull with PU. No glas just poly. Those mounts are solid. See my pics of one of my FX-1s inside and you'll see what I mean. Ive been using the slow cure stuff from Home Depo. Its cheap and very good. You can get "Better" stuff from boat shops or US composites.
The best part is, you have the piece you need from the cut up SN.



See, Yamaha used poly everywhere on this hull. So take your hull fittings from the trashed hull, mount em up, align them, support the engine in place and glue away. The trick is the slow cure stuff holds better but has to cure for a loooong time,

 

[Liquid Graffix]

Thats actually a great idea and a whole lot easier than glass. I did think about the vibration knocking it loose. I'd have to add a lot of glass and it adds weight

I'll check around for the glue instead. Thanx!

 

[madscientist]

try tap plastics...

 

[Melmack]

Every once in a while, I have a god idea. Glad I could help.

 

[Joecochrane]

I don't mean to hi jack your thread but if i were to use the poly adhesive could i just grind down my 300 mounts clean carefully remove my 650 mounts and glue them into to the 300 hull? If this is the case what is the brand name of the glue?

 

[Melmack]

You cant just glue in the mounts alone. You need a large surface area to bond securely. I would say the area used for the fx-1 mounts pictured above would be a minimal amount. You could mount the mounts to an aluminum or SS base if you don't have a chopped up hull to steal from. Then glue the large aluminum or steel base to the hull.

The adhesive Ive been using for gluing wood to wood, auto glass to plastic, brick to mortar with good success is Loctite PL Premium. Don't use the Advanced version as the quick cure time probably kills the bond strength.

You should try this stuff yourself before taking my advice. I haven't bonded a motor with it yet but I'm convinced this is the same stuff that the manufacturers use. Just much cheaper because it doesn't say 'Marine' on it. Kinda like marine silicone. How much more than 100% silicone can you get?

I did a test with a dirty piece of 2X6 to the inside of a butchered wave venture. I didn't even bother to clean both surfaces. After 24hours, it was almost impossible to remove. It wouldn't pry off. I finally got it off by hitting the back side with a log splitter sledge very hard. It took a huge impact to remove it.

 

[madscientist]

if you do this we can make you some shorter mounts for just this purpose.

 

[Joecochrane]

Yeah didn't think of that if you cut up a hull and glue in the mounting area your raising the engine the thickness of the glass. Damn why can't things ever be super easy

 

[WFO Speedracer]

Yeah didn't think of that if you cut up a hull and glue in the mounting area your raising the engine the thickness of the glass. Damn why can't things ever be super easy

It may be easier than you think, set your pieces in there with the engine mounts attached and see how everything lines up.

 

[madscientist]

tru. with the shims and such it cannot be off by much.. i am getting my custom gp-800 conversion height this week i hope. they are almost 1/2 an inch shorter than reg gp mounts and designed for swapping yamaha into kawie with the use of 1/4" plates...

the next evolution,.

 

[Joecochrane]

my build is so weak compared to you guys its embarrassing

 

[madscientist]

plexus two part and a gun would work great for the mounting glue....

 

[Liquid Graffix]

I'm thinking I will grind all the mounts out of the 300, then cut the mounts from the chopped up hull and possibly shave them down a bit to get it to the right height. As for the rest of the mounts I don't think it will matter much.
I'm gonna try to track down the adheisive that is used to bond the top and bottom decks together. I think it's about $80 for a tube, but might be worth it knowing how strong it is.

 

[madscientist]

the plexus is what is used to fuse corvette body panels together... get the 5min not the 60 sec.. .better off getting the 15 min..