Custom/Hybrid 550 motor in a 300sx hull questions

[Joecochrane]

The guy I bought my 550 from said the pump is "fully built" What ever that means I know the prop isn't stock but i don't know what else if anything has been done. I could get a x2 hull with the pump in it for free if its worth it but i would imagine that i wouldn't be able to just cut the pump tunnel out of the x2 and graft it to the sx hull

 

[WFO Speedracer]

You will never get good results with the 440 style pump, I chased and chased my tail for years trying to make that pump work, if you are not willing to do at least a 550 pump swap just leave the 300 in it and ride, it will probably work better.


Well that kinda sucks to hear. I do plan on swapping out the pump just kinda wanted to get the motor in and running first. Will the 550 pump handle a modded 650 or 750 I plan on going that route in the future. Right now I'm trying to piece something together with the parts I have and very little money out of pocket.

This pretty much sums up my life story, the 550 pump will work but the 650 pump works much better, I will go so far as to say the pump limits the ski way more than the motor, a 550 engine in that ski with a 650 pump would probably haul a$$, the opposite not so much.

 

[Joecochrane]

good to know I appreciate the info is a x2 pump and a 650 pump the same?

 

[WFO Speedracer]

Cutting out the pump tunnel and grafting it into the SX hull is exactly what everyone is doing, I am the exception, I made a mold out of the inside of a pump tunnel, cut the old tunnel out , secured the mold into the ski and made a new pump tunnel, IMHO the only correct way to do it, but whatever works I suppose.

 

[Joecochrane]

keep in mind I am just trying to upgrade from my old js hull not trying to build some the baddest freestyle back flip ski on the water. So i guess ill go chop up the x2 pull the pump flip my sx upside down and stare at them both for a while

 

[WFO Speedracer]

There are about a dozen build threads on here and PWCT you can look at for more information before you start cutting.

 

[Joecochrane]

Yeah I've been reading all of them trying to learn as fast as possible. Cutting is nothing new to me do a lot of work on custom rock crawlers just normally use a plasma cuter and welder i have never played with glass before. Probably gonna recruit someone to help me with the glass work.

 

[Joecochrane]

when i set up the motor and pump will i want to push it back as far as possible? I don't see my self ever pulling off a back flip but I do want to build this thing to get as much air as possible. I don't want to carve booeys or ride on my hood Just want to build a ski I can jump as hi and far as possible.

 

[Liquid Graffix]

Then you should use a 750 pump and put an 800 motor in it later on down the road. For the amount of work you will be doing to replace a whole pump section, might as well upgrade to a 750 pump instead of using the 650. The 750 pumps can be removed easier to make changes to the prop and set it up for dual cooling.

 

[Joecochrane]

good to know but now I am so far away from the original plan of pulling my js motor and slapping it in the sx in a weekend so now I would need a 750 hull to cut up and a 750 pump? I got a x2 and pump and I would imagine a 750 pump and haul aren't nearly as easy to come by as a 650

 

[Joecochrane]

Man you guys are killing me the original plan was to slap my 550 motor in my sx hull over the weekend and ride it. Not butcher the thing into a Frankenstein project. I would imagine its not to easy to come up on a 750 pump and hull on the cheap but I don't want to do it twice. Just for motovation how much better will this setup be then my p.o.s. js 550 I have never ridden anything but 440's and 550's.

 

[Liquid Graffix]

Just ride the thing till it blows up or you have enough $ to build another ski the way you want it! Enjoy the one you have for a while, read some more posts / do some research, and after the summer- tear into it for a winter project

 

[Sanoman]

you done any more to your ski?

 

[Joecochrane]

I got a couple other 550's that run rode them last week (it was cold ordered a wet suit the next day) plan on having the sx done by summer. Prob go with the 650 pump since I have it and I think I'm gonna take the 300 out a couple times before i cut into it. I didn't realize that the sx haul had as much potential as it dose until i started doing some research. So I'll take my time try use the best parts i can with the budget i have and get it done in a couple months

 

[WFO Speedracer]

I got a couple other 550's that run rode them last week (it was cold ordered a wet suit the next day) plan on having the sx done by summer. Prob go with the 650 pump since I have it and I think I'm gonna take the 300 out a couple times before i cut into it. I didn't realize that the sx haul had as much potential as it dose until i started doing some research. So I'll take my time try use the best parts i can with the budget i have and get it done in a couple months

Don't worry you are a member of a very very big club on that one.:cool2:

 

[Joecochrane]

Yeah my plan was to try and find a decent 650sx for 1000 bucks or so but I'm starting to realize I will be way better off putting a grand into building 300sx. My Js550 out runs my friends limited 650 anyways but i got a lot of motor work

 

[Joecochrane]

Ok I got a 750 pump and a hull to cut up I think its a zxi I pick it up tomorrow and i got a guy to help me do the glass. So now i just need to do a lot of research on cutting the pump housing and and grafting in the new one. I'll do all the thread searching I can on this but the more you guys chime in the faster I will learn.

 

[Liquid Graffix]

Welcome to the club!

 

[Joecochrane]

Haha thanks man now any tips you can give me would be great I'm gonna start glass work next week I need to do a lot of reading on how to reinforce the haul. I got a lot to learn on ski setup to I don't know anything about motor and pump location. I want to fly as hi and far as possible not looking to do a bunch of tricks or stunts just want huge air. So do I still want my motor and pump as far back as possible or should I just try to center the bigger motor over the stock location?

 

[Liquid Graffix]

If you aren't trying to do anything crazy, then you dont have to worry about setting the pump back. Just set up the motor for a lot of bottom - with a good pipe - end and make sure you have a good prop.

I'm just now to the part of my 300 build where I am getting ready to glass the pump housing back into the 300 hull. I cut the SJ bottom all the way up to the bulk head so I could use the midshaft and everything will line up. As far as the motor mounts, you will need to make a plate that either bolts to the 300 original mounting points and then bolt the motor to the plate OR glass in new mounts. I'm going to cut the SJ mounts out of the old hull, grind down the old ones in the 300, and glass the SJ mounts in.