Emulsion tube not staying

I cleaned the carbs on my '83 xj750 seca, but I'm not sure if I'm doing something wrong because the emulsion tube (just to be sure, the tube that the Main jet screws on to)on carb 2 and 3 does not sit tightly and would move sometimes. Not sure if this is the cause of my bike not keeping a consistent idle or for that matter start every time on the first time.

Everytime I've tried to start I've made sure the battery were 100%, fuel was being supplied. Tomorrow I might be going to a local bike shop to see if they could help.

Any advice/info would be greatly appreciated! Was trying to get her at least running good before I possibly leave for afghanistan.. again lol

 

If you somewhat gently, but firmly force a Phillips into the Emulsion tube, while tighening the Main Jet, you will be able to snug the thing down.

You don't want to mar or deform the tube

You don't want to involve a mechanic for something this simple,

You don't REALLY want to go to Afghanistan - - there's no good riding roads there !! But you then need to completely "winterize" your bike so it will be all good when you return. Oil the Cylinders - drain and spray-out the carbs. Coat the tank with oil. Vaseline the chrome, "Pledge" the bike.

 

Break the lead off a Sharpened Pencil.
Dress the end with an Emory Board.
Use the taper to hold the Tube from rotating.
Or
An Artists Paint Brush.

 

Thanks TimetoRide and Rick! I'll be attempting to tighten her up today.

 

Although it might seem like more work, I'd go with either of Rick's ideas over Time's, simply because that emulsion tube is brass, and a phillips will definitely mar the opening (also considered a "jet").

I usually just stick a finger into the venturi and hold it down from there (I think, it's been a while since I rebuild my hitachi carbs, and mikunis have slots that hold the emulsion tube). Once the jet tightens a bit, friction should keep the tube from rotating. And the jet only needs to be a little snug, it's also brass.

Stabil the tank and run it through the carbs too. Depending on how long you leave the bike, don't feel bad if a quick carb clean will be in order when you get back.

 

Thanks ManBot, I was leaning towards the softer material to hold the tube down. I had the impression that the friction would hold the tubes down but when I checked the CV slides to see if they perform accordingly the tubes would sometimes ride up with the needle attached to the slide...

Do y'all think that might be an issue for the bike not staying on consistently? Like I said before there are times (just a handful of times) where I would start the bike (with full to half choke and setting the petcock first on "On" then "Pri" also with a fully charged battery) and she would hold idle below 1k rpm and I would sometimes be able to open up the throttle. But rest of the time I've tried she either won't start or would start hold idle for a bit (it would sometimes be weak) but as soon as I let the choke down or open up the throttle she dies...

I'll be doing everything I've read through searching the forums. It sucks that I'm in somewhat a tight schedule.

Thanks!

 

Dumb question.....are you missing a brass washer at the bottom of the tube that will anchor the tube in place? Sounds like the washer is not there. If it is, then you have a stripped thread or something that is not allowing the jet to seat itself all the way.

Dave Fox

 

Buy a small can of Marvel Mystery Oil.
LockTite RED #271
Take pictures of how the springs and linkages fit.
Do one at a time.

Grind the backs of the Throttle Plate Screws.
Those Screws are staked too prevent loosening.
Mark the Throttle Plates with a Scratch-awl. Up arrow and Number.
(So solvent wont let marker get washed-off)

http://www.electricaladvantage.net/pick ... cekit.aspx

 

I agree with hogfiddles. When I said friction, I meant the friction on the top "ring" or "ledge" of the emulsion tube that pushes down on the carb body. It's not an "interference fit" (although it can feel like that at times) and the main jet doesn't hold the emulsion tube in place, the brass washer does. The jet isn't wider than the emulsion tube.

Your emulsion tube, getting stuck to the jet needle and sliding out, will indeed keep your bike from running right.

 

So the "dumb question" actually solved my issue lol, I'm not sure if I should feel dumb or not . I just sent Len an email seeing if he had some in stock. Thanks for all the information Rick, ManBot, and Hogfiddles!!

I'm sure the PO wasn't sure what he/she was doing.. When I took apart the carb, on carb #3 there was a #124 main jet while the others were 120 with some generic pod filters.

 

That's the third carb If come across this year with a washer missing under the jet! I even came across one where the washer was there, but the jet washeld in place with a tiny dab of JBWeld because the threads were broken off.

I find funny stuff in sled carbs, too..........though those are a whole lot simpler--at least the mid 90's polaris indy ones

I actually find myself having fun taking carbs apart now, rather than the fear that I used to experience a few years ago.

dave F

 

It's fun when they come-apart without a fight.

Stuck Fasteners, Jets, Pilot Mix Screws and Float Hinge Pins make it less enjoyable.

 

why does this forum call the needle jet a emulsion tube ?
and what do we call the jet needle then? a emulsion needle?
a emulsion is two liquids that don't mix

 

Hint: Air, for the purposes of dynamics, is a fluid. It's just a difference of British vs. American "English" terminology. Since Japanese have a long history of building British products under license they adopted British terminology (mostly).



[EDIT] This deserves a clearer, and less smarta$$y, answer.

In Physics gasoline and air are both considered fluids. When gasoline is siphoned into the airstream and blended ("atomized') an emulsion is created. The gasoline never mixed into solution with the air, it's just suspended in the form of tiny droplets riding along in the airflow.

Imagine oil and egg yolks; oil is the gas and the egg yolks are the air. Drizzle in the oil as you blend the egg (with sufficient, but not too much, speed) and you suspend tiny droplets of oil in the egg. Now you have yummy mayonnaise. Blending an air/ fuel mixture isn't much different in principal (though it's not nearly as tasty).

 

I try to refer to it as "Nozzle"

That's what it's called in the Parts Diagram.

 

K-Moe thanks for that, definitely explains a lot!

 

i like that, i think i'll call it the mayonnaise pipe from now on

 

well, it depends on where you're from, and sometimes what diagrams you're looking at, and sometimes what company you're dealing with........some places it's called the emulsion tube, o the needle jet, the fuel nozzle, mixing tube, etc....

It get's especially confusing when some places refer to the fuel inlet needle as the needle jet, when it's also referred to as the fuel needle, float needle, float jet, etc.......

When I'm talking with someone I try to listen to what their set of terms is and adjust mine to match. That way we speak a common language for a minute, even if they don't know what the problem is...... LOL

Dave F

 

So I got the washer for the main jet/emulsion tube thanks to Chacal/Len! She starts every time with no starting fluid!

But... High rpm on idle, I'll do my research now

 

Fine with me, so long as you don't start smoking the mayonnaise pipe. That leads to no good.