1200 GoldWing Float adjustment ?

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....

 

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.

 

That should have been

"insert a hunk of plastic >>tubing<< looping back up
in the air and use that as a sightglass.

 

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?)

 

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.

 

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.

 

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 spring would have to be very weak, or the float very heavy for
this "problem" to occur when following the shop manual procedure.

 

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.

 

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 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.

 

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.

 

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.

 

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.

 

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.

 

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.

 

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 ?

 

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.

 

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 ?

 

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.