1200 GoldWing Float adjustment ?

Discussion in 'Motorcycle Technical Discussion' started by Runk, Jun 20, 2009.

  1. Runk

    Runk Guest

    Been a Gear head my whole life , But I'll be damned if I can get it through
    my thick head how to set these floats to Spec . I've got a diagram of how
    it's done but I aint getting it. Any one got any help for the dim wit !
    Thanks Runk....
     
    Runk, Jun 20, 2009
    #1
    1. Advertisements

  2. Never worked on a wing, but on my bike, I figured out
    the depth of gas I wanted in the bowl, put a mark
    on the inside of the bowl and adjusted to that mark
    by tweaking the tab on the float which pushed on the
    needle.

    I found all kinds of arcane directions about adjusting the
    floats by sight. I found depth of gas to be a way better
    method. Turn the tap on then off, then drop the bowl.
    There should not be significant additional flow from the
    line because of vacuum.

    People suggest that if you've got a carb drain screws, you
    can remove the drain screw and insert a hunk of plastic
    looping back up in the air and use that as a sightglass.
    Level of gas in the tube will match level of gas in the bowl.
    Not applicable on my Bing carbs, but sounds like a good
    way to do it if possible.
     
    Rob Kleinschmidt, Jun 20, 2009
    #2
    1. Advertisements

  3. That should have been

    "insert a hunk of plastic >>tubing<< looping back up
    in the air and use that as a sightglass.
     
    Rob Kleinschmidt, Jun 20, 2009
    #3
  4. Runk

    paul c Guest

    I wonder just what is the typical reason for needing to adjust floats,
    apart from previous mishandling. Wear? Fatique? Mis-adjustment of
    other parts?

    (Sometimes I wonder if it's most often just because nearly every shop
    manual gives an adjustment value and it's very easy to misinterpret
    where the float should line up with the body, somebody gets it wrong and
    an endless adjustment cycle ensues. Say a bike has less than 50K klics
    on it, with no physical damage, are any other reason more likely?)
     
    paul c, Jun 21, 2009
    #4
  5. Plastic floats do seem to eventually loose buoyancy
    and need replacement. When they're replaced, the
    new floats need to be checked and maybe adjusted.
    The floats may also need to be removed to remove jets.
     
    Rob Kleinschmidt, Jun 21, 2009
    #5
  6. Runk

    ¿ Guest

    Floats mostly get adjusted in error, by a shade tree mechanic that
    doesn't really understand how carbs work or what to do when they get
    gummed up from fuel evaporation.

    And, said mechanic often doesn't really understand how to achieve a
    higher or lower fuel level in the float bowls, and the instructions in
    the repair manuals might as well be a Tibetan mantra, for all the good
    they do him.
    Every manual I've ever read specified a certain dimension from the
    bottom of the float to the gasket surface (not the surface of the
    gasket!) of the carburetor body, while the carb is upside down on the
    bench.

    When the carb is upside down, the bottom of the float is uppermost, so
    the dimension becomes from the top of the float to the carburetor
    body.

    Increasing this dimension causes the float valve to shut off the fuel
    sooner, reducing the level of fuel in the float bowl. The engine will
    run slightly leaner at idle.

    Decreasing this dimension causes the float valve to shut off the fuel
    later, increasing the level of fuel in the float bowl. The engine may
    idle slightly too rich.

    Say a bike has less than 50K klics
    on it, with no physical damage, are any other reason more likely?

    Nah! If it ain't broke, don't "fix" it. Just add a good carb cleaner
    like B12 to the gas
    in the springtime, and ride the carburetors clean.
     
    ¿, Jun 21, 2009
    #6
  7. Runk

    the fly Guest

    Unless the needle valve has a tiny, spring-loaded plunger that
    actually makes contact with the tang on the float. In that case, the
    carb should be on its side, not upside down, to measure the float
    level. With the float pivot pin at the top, and the float hanging
    "down," tip the carb body until the float tang BARELY contacts the tip
    of the plunger, without compressing it. This can make as much as 3-4
    millimeters difference in the fuel level in the bowl, affecting
    performance and mileage accordingly.

    In my experience, lots of carbs come from the factory with
    float levels poorly set. (Ditto for ignition timing, carb sync, valve
    clearance, etc.).
     
    the fly, Jun 22, 2009
    #7
  8. Runk

    ¿ Guest

    The spring would have to be very weak, or the float very heavy for
    this "problem" to occur when following the shop manual procedure.
     
    ¿, Jun 22, 2009
    #8
  9. Runk

    TOG@Toil Guest

    In my experience, this is utter bollocks.

    Quite apart from anything else, carbs are getting rare on Jap bikes
    these days, and unless you actually check(ed) carb settings and valve
    clearances on brand new bikes as a matter of course, I don't see how
    you can justify a statement like this.

    "The factories send their bikes out with everything to cock" is what
    you're saying, really.
     
    TOG@Toil, Jun 22, 2009
    #9
  10. What really escapes me is why adjust by when the
    float makes contact instead of by height of fuel in
    the float bowl. I find the lattter proceedure way saner.

    After having to swap some elderly floats and struggling
    to adjust by point of contact, I eventually took a mototool,
    scribed a couple lines on the inside of the float bowl,
    and adjusted the floats, using fuel level as a guidline.
    Way more satisfactory and consistent results, much more
    readily obtained.

    Previously, the bike had been experiencing symptoms
    of fuel starvation at high speeds. I raised the fuel level
    and the problem was fixed. I may go back in one more time
    and fiddle a little more to see if I can get by with a lower
    setting as I'd like slightly better mileage, but this method
    strikes me as way easier and more repeatable than
    trying to eyball the float.

    Only reason I can think of for adjustment by point of contact
    maybe some difficulty in removing a float bowl without spilling
    fuel. Otherwise, the whole exerise seems totally silly. It also
    assumes absolutely constant buoyancy, which in my opinion
    may not be true over the lifetime of a plastic float exposed to
    alcohol blend fuels.
     
    Rob Kleinschmidt, Jun 22, 2009
    #10
  11. Runk

    paul c Guest

    Rob Kleinschmidt wrote:
    ....
    I can see that 'swapping' is likely to necessitate float adjustment,
    along with side-effect of disassembly, also suppose that manfacturers
    don't scribe lines because can't be sure what jets will be used and what
    engines the carbs may be sold with.

    I've tinkered with bending the tangs on friend's bikes a few times, when
    trying to decide if the actual level was 21 mm versus 22, I tried to aim
    for the lower number on the theory that slightly richer makes the engine
    run cooler.
     
    paul c, Jun 22, 2009
    #11
  12. Runk

    the fly Guest

    Exactly. And that difficulty exists in well over 90 per cent
    of all carbureted motorcycle engines. (Try getting at the inner carbs
    on an inline four). Accuracy can be had with an appropriately-sized
    steel scale and a little practice.
     
    the fly, Jun 22, 2009
    #12
  13. Runk

    the fly Guest

    That has been my practice with new bikes for quite a number of
    years. I usually do what amounts to a major tuneup within a week of
    purchasing a new vehicle. It has never failed to make a noticeable
    difference.
    It's usually better in the case of EFI, and hydraulic valve
    actuation.
    A few experiences with prematurely blued exhaust pipes, crappy
    idling, and poor performance will do that to you. I stand by my
    statement. As long as it runs (even poorly), the factory is always
    under pressure to ship it.
    That's been true of motorcycles, automobiles, and industrial
    diesel engines alike, through a few decades of my involvement with IC
    engines.
     
    the fly, Jun 22, 2009
    #13
  14. Sorry, but I don't belioeve it. I've owned new bikes, and never had a
    problem. I've known lot of people who've had new bikes, and they've
    never had a problem.

    Now, after a week, I'd expect (on some bikes) things to settle down, bed
    in, and that's why manufacturers have a 500-mile service.

    I still think you're talking total cock. Sorry and all that.
     
    The Older Gentleman, Jun 22, 2009
    #14
  15. Cranked screwdriver and a mirror-onna-stick works for me.

    That said, modern carbs (that is, the last generation now that EFI is
    taking over) are so bloody good that faffing about with them was/is
    practically unnecessary.

    Older carbs - yeah, well, a different matter. I've spent more time on my
    400F's carbs than on the carbs of all the other bikes I've ever owned,
    combined, I think.
     
    The Older Gentleman, Jun 22, 2009
    #15
  16. Runk

    the fly Guest

    If you've had better luck than I, so much the better for you.
    The only BMW twin I ever owned, blued ONE header pipe on the
    way home from the dealer. The carbs on my 1200 Bandit were similarly
    out of sync.
    And don't even get me started about the condition of quite a
    number of Lister diesel engines with haphazard tuning "right out of
    the box." Supposedly all been dynamometer tested before dispatch.
    Fine old English craftsmanship, my eye.
     
    the fly, Jun 22, 2009
    #16
  17. Maybe that says something about the dealer(s) ?
    And are you talking carb or float adjustment ?

    Why would you pay perfectly good money to a dealer
    to put a bike out of tune when you can accomplish the
    same thing in the garage with only few minutes tinkering ?
     
    Rob Kleinschmidt, Jun 23, 2009
    #17
  18. Runk

    the fly Guest

    Or the factory assembly process.
    It was mostly carb synchronization (or lack thereof).
    I generally DON'T let anyone else do work that I'm equipped
    for. The instances I mentioned were of new machines delivered, and
    badly prepared, by factory, dealer, or both.
     
    the fly, Jun 23, 2009
    #18
  19. Call me old fashioned, but I'd expect the dealer to
    check out and correctly set up any bike they sold
    before it went out the door. Maybe that's changed ?
     
    Rob Kleinschmidt, Jun 23, 2009
    #19
  20. Runk

    the fly Guest

    Old-fashioned it is. I feel the same way, but proper tuning
    and set-up of new vehicles is mostly conspicuous by its absence. Some
    care, most don't.
     
    the fly, Jun 23, 2009
    #20
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.