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What is an Emulsion Tube?

Discussion in 'Technical and Troubleshooting Torque' started by WiErD, Mar 22, 2006.

  1. does anyone know what an Emulsion tube is.

    mine are apparently leaking, according to the mechanic

    as i didnt have the tools for a carby balance after my rebuild and it running like crap -

    high rpm for no reason, butterflys definately closed - verified with tank up.

    i thought at first it was a vacum leak but ive tightened everything to an inch of its life.
    then i thought the carbs are prolly out of balance from sitting around.
    i first gave them a bit of a once over with some carb spray on cleaner.

    after checking and rechecking, i eventually gave in and took it to a workshop to balance.

    the result i got back is they adjusted the carbs, but there not very far out, the emulsion tubes are leaking, and carbys require strip down and possible overhaul.

    anyone know or have any suggestions?
  2. Hi wierd. Emulsion tubes are the brass piece that have a lot of micro holes around them. They sit on top of the Main jet. Have seen some that have the needle guide built into top and some that have a seperate needle guide that sits on top. Not sure about your GSXR. As to them leaking, mmm. The needles and guides can wear enough to give you a rich runner in the just above idle to quarter throttle position. Some needles have grooves and circlip to lower and change mixture in that range.
    Cant make out this line. high rpm for no reason, butterflys definately closed - verified with tank up
  3. what i mean is it will be idling along just sitting there at around 1100RPM then it just jumps to 5K without even touching the bike.

    the butterflies are closed coz i can prop my fuel tank up and see the position of the throttle.

    ive just disasembles all the carbs and given them a good clean out, everything is in the place it should be, no gunk, nothing blocking anything..

    but i did notice that its got less than the usual amount of kick, untill about 10-11K RPM, so maybe the jets are screwed?
    do the jets work on throttle position or rpm? i thought it was position so my theory might be incorrect.
  4. The jets do work on throttle position. Starting from idle, the mixture screw is working. just over idle to part throttle opening, pilot jet. Part throttle opening, jet needle and half throttle to full work off main jet. These all overlap with throttle opening.
    If rpm increases without throttle opening, it sounds like it is running lean. l'd be looking for a vacuum leak of some sort. Balance connection point, manifold ect.
  5. i might have found the culprit, not enough valve clearance.

    ive measured them all, 2 valves (on seperate cylinders, both on exhaust side) have not enough clearance.

    i might be able to switch a few shims around to get them all the right clearance, otherwise ill have to get them machined down.
  6. In answer to your origional question -an emulsion tube is an introduced metered air leak which works on the main fuel circuit. Pretty much at wide open throttle. As the volume of air increases through the venturi the air/fuel ratio starts to head to the rich side of the scale. If you ever happen to see an emulsion tube you will notice a series of small holes drilled in it. This introduces air into the fuel & brings the air/fuel ratio back to where it should be. If you're really keen you can play around with them -blocking or drilling more holes to produce more top end power or better economy. Best you are friendly with a dyno operator though :LOL: :LOL:

    Personally, I would not surface grind the shims. Some are case hardened & you may go through the hardened layer. Plus the etched numbers on them will loose their relevance -giving some poor b@gger nightmares down the track if he doesn't happen to own a micrometer.
    Best just to get friendly with your local Suzuki dealer & exchange with them -at a price of course. My local shop will swap any number of shims for a set price. But it is a Honda shop :wink:
    Good luck. Nearly there now.
  7. Clearly, sir, your motorcycle wishes to wheelie, with or without your encouragement. This is perfectly normal for a GSX-R, and a sign that your bike has a healthy self-image.
  8. Or you could do the correct thing and just order some replacement shims in the appropriate sizes.
  9. [quote="koma]
    Or you could do the correct thing and just order some replacement shims in the appropriate sizes.[/quote]

    i could, but wheres the fun in that.

    anyway, i got all the clearances to within there specs, still the same thing:(

    i dont know what else to try now, im thinking its def a vacuum leak somewhere, because it doesnt do it all the time.

    runs like a dog when its dead cold ( in the mornings) you can give it full throttle and it wont go anywhere, rpm wise, and when it does if you try and ride out the drive with less than 4K on the taco, it wont go anywhere.

    after it warms up a bit from the ride to work, around 15 Minutes of highway driving, it seems to settle down sometimes. then as you pull in to the first set of lights slow down, pull the clutch in up it goes to around 5K

    so im thinking, heat expands something thats causing this problem from when its cold, and creating another when its hot..

    oh, and the power is no longer there, if you do a 3rd gear runout from around 60K's or so, it will hoon along untill around 11K then you feel the power just kick in, it never used to be like that :( <-- this is true for any gear.

    if anyone can shed some light, id appreciate it :)
  10. An Emulsion Tube?

    Isn't that what they fire the Photon Torpedos out of
    on the USS Enterprise? :LOL:

    Don't worry about me chaps, it's been a long night-shift here. :LOL:
  11. The problem is most likely associated with the carbs (although it could be something simple like crud in your fuel lines). Valves out of adjustment will not cause fluctuations in the rpm and running problems like you're describing.

    Check that no fuel lines are being pinched by the tank etc, and that all connections to the fuel tap (and inside it) are clear.

    The most likely way that you'll get to the bottom of this is by stripping and inspecting the carbs, and giving them a full cleanout. The emulsion tubes, needle jets and main jets could all be possible culprits (might as well clean the pilot jets while you're there), or even a stuck float chamber. Use compressed air to clean these out.

    It's not a hard process, just time consuming. Best way is to get a workshop manual which explains the process in detail. If you've got the time then it's most economical to do it yourself.
  12. Definitely carbs, but you now know that. I don't mean to add to the theories, but I'd be checking the float bowls: the valves and float heights. The diaphragms (rubber sheets on top of the carbies, that hold the slide and needle) should also be nice and airtight, with no holes. Carbies can simply wear out and get sloppy, with visible needle wear in the main jets. Finally, make sure all the rubbers- the airbox-to-carbie and the carbie-to-cylinder head rubbers are airtight and clamping nicely.

    My condolences as you have a bastard problem and taking carbs on and off, and apart, is not fun.
  13. ok i found the problem

    i won the battle, but the war is still going.

    turns out my manual showed the starter clutch cover upside down, and vague instructions, so timing was out.

    its now all good, except for a ticking noise i hear at different rpm, and when deccelerating.

    i have a feeling its the cct (cam chain tensioner), even though its a new one, and less than 1000K's on it, but i did take it off a fair few times and screw it in and out alot.

    anyone know how to diagnose for sure if it is?
    i was thinking just getting a manual one, but cant seem to find one :(