Finally scored a Factory Pipe for my 750sx. Will need help jetting

R

roman

Location
detroit
Hey guys. So I scored a factory pipe for my 750sx, 700 bucks plus my stock exhaust. Not great but not bad given the current market.

My 1994 750sx is bone stock, other than rideplate and intake grate. Single Keihin Carb.
What am I going need to to order jet wise? I once found online the FP recommended jetting but now I cant find it. Want to place my order into JetManiac so I can Brap it right away.

Anyone have recommendations for where I should start off with carb jetting? What about water screw settings? Im after low-midrange grunt.


Once the season is over, The plan is to pull the motor. I have a 750 ss xi that I want to pull the high comp head from (bright green), it also has the dual carbs, and I have a spare ebox from an sxi with the better ignition curve. Should make an honest 80-85 hp right?

Thanks for the help guys!
 
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S

sturat

Location
WA state
That's probably the lowest a 750 factory pipe will ever sell for, outside of the dry pipe. $700 and stock exhaust is a total steal... I sell the exhausts alone for $1500 regularly.

My advice is get a mikuni adapter for your stock manifold and go to a single sbn44 as opposed to building up the stock keihin. You'll get way better overall performance and tuning will be much easier. The single keihins are good for stock skis but most of the time I will go mikuni.

Which pipe do you have? The mod or the limited? The mod wraps around the front of the engine and does not go to the waterbox. The limited is the big fat centerbleed chamber that goes back to the waterbox.

from the FPP site:

Recommended Carb Adjustments:
These adjustments are for sea level on a stock engine with aftermarket flame arrestors.
Your specific adjustments may vary depending on modifications, fuel, altitude and other
variables. Please consult a qualified technician if you are not familiar with tuning your
carburetor.
750SX
Main jet : 155
Pilot Jet : 88
High speed screw : 7/8 turn out from closed
Low speed screw : 5/8 turn out from closed
Needle & Seat : Stock
Spring : Stock
 
R

roman

Location
detroit
I got the Limited exhaust. Cant believe this is a steal. I had the opportunity to pick one up for 500 plus my exhaust a while back but ended up staying at my moms when she broke her back, so I missed out.
Cant bring myself to spend anymore money outside of getting a new prop and a handful of jets. We are building it for "freestyle", which is pretty dumb if it isn't a SJ lol. My other ski is an 08 SJ though.....But I like the feel of the kawi sometimes, especially when I feel like pulling some big ole slides.
 
S

sturat

Location
WA state
You paid less than half of market value so yeah it's a steal.

>We are building it for "freestyle"

Save your money or get it running with the specs I posted and sell it. You are going to be severely disappointed.
 
R

roman

Location
detroit
sturat said:
You paid less than half of market value so yeah it's a steal.

>We are building it for "freestyle"

Save your money or get it running with the specs I posted and sell it. You are going to be severely disappointed.
Click to expand...
Ya I know it’s not a freestyle ski. But I like the way it rides so it’s staying in the fleet. We have the full bolt ons Superjet for actual freestyle, and the 750 ss xi for sitting down. They all have their pros and cons….but the sj has the least amount of cons I’ll give ya that.
 
M

Mentzel

Location
Ak
Man don’t make it a freestyle ski.. Its a race hull. So many other choices for freestyle these days. Make it a super clean limited 750. It will hold value well. These are becoming rare to find parts for.
 
R

roman

Location
detroit
I mean what really makes its freestyle vs race......just how you ride right?
In that regard I guess when I ride it, I do like to see how tight I can turn and and see how much lean I can maintain while turning. Its definitely better at leaning over than my SJ I think. But I also like to do big ass slides with it, submarines, bob up and down thing, 180 slides.
What Im not going to do is chop it up or anything. Dont want to shorten it, dont want to extend it, dont want to rocker it. The only fiberglass work its getting is a restoration of the bottom, and *maybe* footholds.

Motor wise, Ill stop at full bolt ons.
 
S

sturat

Location
WA state
the SX hull is a straight up turd no matter which way you wipe it down or dress it up. The SXI Pro is a much better hull.

Some handling mods and that pipe will make it a fun Huffy/Mongoose of the fleet. I wouldn't waste your time or money trying to make an apple out of an orange.
 
R

roman

Location
detroit
sturat said:
the SX hull is a straight up turd no matter which way you wipe it down or dress it up. The SXI Pro is a much better hull.

Some handling mods and that pipe will make it a fun Huffy/Mongoose of the fleet. I wouldn't waste your time or money trying to make an apple out of an orange.
Click to expand...
Ya that's what Im going for. Something fun in the fleet!

Thanks for the jetting specs though!

What do you think they would be if I bolted the duals from the ss xi right away? Im thinking the duals will give me more power everywhere.
 
S

sturat

Location
WA state
roman said:
Ya that's what Im going for. Something fun in the fleet!

Thanks for the jetting specs though!

What do you think they would be if I bolted the duals from the ss xi right away? Im thinking the duals will give me more power everywhere.
Click to expand...
They will. Whatever the screws are at stock, I would turn them out one turn each and go from there. The Triple jet keihins can be a little tricky to tune but we ran them on a buddy's big pin 750 with pjs pipe for a year with no issues before going to dual 44s. It will be a lot of trial and error but as long as you check plugs it should be pretty painless. Helps to tie the ski up for a power tune.
 
R

roman

Location
detroit
So I actually have a stock Superjet 650 engine in my garage. Is that an sbn44 you think? Would that technically be an upgrade here over the keihin ?
 
kevbo

kevbo

Location
dfw
Your 44 will work okay, just find a way to attach it and bore the hole to match. It will wake up the pipe a little.
 
R

roman

Location
detroit
Ok So I've installed the pipe. Did some carb tuning (thanks for the advice Kevbo) on the stock keihin. Im not swapping it out as the season is done for us in 2 months.

Now my new problem is I feel like I maybe lost power down low, and then all of a sudden tons of power. Girlfriend doesn't like it and almost wants the stock pipe back on for more linear power. Ill admit it kind of is a bitch to ride now so I gotta fix it. So now I need to mess around with the screws some more and write down what I actually did.

Since the bottom screw is impossible to get too, Id like to know what settings anyone has used that yielded the most low end grunt. Im guessing bottom closed, middle closed and then play with the top screw.

edit. I should also ask, other than maybe richening it up a bit and letting them warm up a little longer, is there any concerns with running these skis into decemeber (water temp of 32-33F)?
 
Mike W

Mike W

Infidel
Location
North Florida
roman said:
Hey guys. So I scored a factory pipe for my 750sx, 700 bucks plus my stock exhaust. Not great but not bad given the current market.

My 1994 750sx is bone stock, other than rideplate and intake grate. Single Keihin Carb.
What am I going need to to order jet wise? I once found online the FP recommended jetting but now I cant find it. Want to place my order into JetManiac so I can Brap it right away.

Anyone have recommendations for where I should start off with carb jetting? What about water screw settings? Im after low-midrange grunt.


Once the season is over, The plan is to pull the motor. I have a 750 ss xi that I want to pull the high comp head from (bright green), it also has the dual carbs, and I have a spare ebox from an sxi with the better ignition curve. Should make an honest 80-85 hp right?

Thanks for the help guys!
Click to expand...

 
R

roman

Location
detroit
Mike W said:
Click to expand...
Ya I’ve used that but I don’t like the instructions as I’m reading on forums for the most bottom end hit you have the bottom and middle shut and just play with the top? So I wanted to see how people here have it set up.
the reason I don’t like the instructions is because the bottom screw is not accessible at all. That’s the screw they want you to play with.
Also side note for anyone reading this. My head pipe bolts that bolt to the manifold have backed out twice now, and I used lock tight the last go around. I met someone at the lake yesterday and he said he had to tighten those bolts every ride when he had his pipe.
Sadly when my pipe blew off yesterday, I lost a head pipe bolt in the engine compartment (better not have fallen into the ex manifold into the engine lol ) and it blew out the exhaust gasket so we just rode the SJ.
So I think I’m going to safety wire these bolts into place, and if you have this pipe I recommend you do the same if you find they are backing out.
 
fastgtfairlane

fastgtfairlane

Location
Charlotte, NC
i personally prefer the top adjuster screw because its easiest to reach and also the closer the water injects to the engine, the more dramatic affect on power it will have. on my sj i have the adjuster screws set to 1/2 turn open on top screw 1/4 turn open. on my x2 with a 750, i run 1.25 turns out on top screw and 1/2 turn out on mid screw. to get the pipe tuned for your riding, you will need to tune it yourself. just make sure at least one screw is open 3/4 turn out to stop possible damage to pipe. i also run a parallel cooling setup where i have a dedicated line coming straight from the pump to the bottom of the headpipe. regarding the headpipe to manifold bolts backing out, it sounds like the threads are worn and will need a helicoil or timesert to properly fix that issue. the bolt is a m10x1.25 pitch bolt. id plan to do all three bolt holes.
 
Mike W

Mike W

Infidel
Location
North Florida
roman said:
Ya I’ve used that but I don’t like the instructions as I’m reading on forums for the most bottom end hit you have the bottom and middle shut and just play with the top? So I wanted to see how people here have it set up.
the reason I don’t like the instructions is because the bottom screw is not accessible at all. That’s the screw they want you to play with.
Also side note for anyone reading this. My head pipe bolts that bolt to the manifold have backed out twice now, and I used lock tight the last go around. I met someone at the lake yesterday and he said he had to tighten those bolts every ride when he had his pipe.
Sadly when my pipe blew off yesterday, I lost a head pipe bolt in the engine compartment (better not have fallen into the ex manifold into the engine lol ) and it blew out the exhaust gasket so we just rode the SJ.
So I think I’m going to safety wire these bolts into place, and if you have this pipe I recommend you do the same if you find they are backing out.
Click to expand...

I always closed the bottom and middle and opened the top adjuster about 1/8-1/4 turn out. Ran great and the pipe stayed relatively cool.
 
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