Carb "experts": what does this thing do?

[Egaeus]

In the carb bowl there is a thin "tube" that sticks down.  The float has an L-shaped tube sealed with an o-ring that goes over it.  What is the purpose of that thing?  I can't even theorize as to what it does.  I searched, but searching doesn't turn much up when you don't know what it's called.

[Jughead]

It's the Over Flow.

[Egaeus]

It's the Over Flow.

It can't be the overflow.  It's the reason my bike wasn't running right.  That, and there's no reason for the overflow to have an o-ring. 

[Jughead]

Oh Sticking own Instead of Sticking Up towards the Carb Body.OK OK........ it's the...... I have no Clue.

Likemy Neighbor Dumb A$$ Neighbor asks me all of the time when I work on Something."Is that the Orifuss Valve?" I always Say "Dumba$$ Do you even know what an Orfice Valve is?"

[starwalt]

Are you referring to the plastic tube with the O-ring that is part of the float assembly?

If you are referring to the plastic tube with the O-ring, this is part of the "Starter System" as referenced by the OEM Suz manual. Fuel is pulled up the plastic tube at the angle cut and up into the brass loop that runs outside the main carb body. The fuel is then in the area that the choke linkage moves and enters the carb throat and the intake of the engine.

In short, that's where the gas comes from for the Choke setting.

If we are talking about the same gadget.

[baco99]

when are we supposed to pull the choke open?  the manual says to start the bike cold with the choke closed; which seems counter-intuitive to me. 

[Wrecent_Wryder]

[4

[Gisser]

Stumbling over semantics, I think. A true choke (which ours isn't) is a butterfly valve over the carb throat that you "pull" closed, not "pull open". So, yeah, you'd close it to start the engine cold.

Although conventional wisdom says different, the GSTwin choke actually works pretty much like any other choke when all is said and done.  In this case, the butterfly valve is the throttle plate, the closed throttle creates a vacuum, the choke lever opens up a bypass circuit and an extra rich air/fuel mix is drawn in.   As the throttle (or butterfly valve) opens, manifold vacuum decreases and the choke effect disappears--no matter that the choke lever is still in on position.        

[baco99]

so then why is it that when the bike is running, and the choke lever is pulled forward, creating the bypass, the bike stalls?  too much gas and not enough air? or is my choke not working...?

[Gisser]

so then why is it that when the bike is running, and the choke lever is pulled forward, creating the bypass, the bike stalls?  too much gas and not enough air? or is my choke not working...?

Idling?  Cruising?  The choke has no effect at highway speed.  Mine don't.  Try it.   

[baco99]

idling.  when the bike is idling, and you pull the choke level towards you, the engine accelerates for a second and then starts to die. 

never tried it while at speed.

[starwalt]

idling.  when the bike is idling, and you pull the choke level towards you, the engine accelerates for a second and then starts to die.

My latest 90 also does this after it warms up. In general - and we have discussed this in some other threads - this is an indication that a cleaning is due for the carbs. The engine is dying due to fuel starvation. My manifestation is a very large change in RPM when stopping to idle and a slight addition of the choke lever.

In short - go through the carbs and clean them.

[Egaeus]

Back on-topic, how is that the choke?  The orifice that's attached to the carb body is too small to put a wire from a brass wire brush through it.  I just stuck my compressor's blow gun on it and hoped for the best.  That, and my choke worked.  How is that possible when the orifice in the carb float was completely blocked on one carb, and almost completely blocked on the other.  And why did it affect the running of my bike, even when the choke was off?

[The Buddha]

Show me a pic. Or [oint out a number in the parts schematic in bike bandit or somehting.
Cool.
Srinath.

[Egaeus]

It's not in the parts schematic.  There is an o-ring on the float.  That o-ring "seals" the part I'm talking about. 

[The Buddha]

It's not in the parts schematic.  There is an o-ring on the float.  That o-ring "seals" the part I'm talking about. 

Oh I get it ... I will check it tonight and tell you. I think it just holds the floats up ... though the bowls being bolted in really are what hold it up. it just holds it up when float bowls are off.
Cool.
Srinath.

[starwalt]

Ok, I couldn't stand it anymore...here's an image of a carb (upside down) showing what I think you are talking about.  Click on it for a bigger/better picture.


IF it is what you asking about, see my first post in this thread about the "Starter System" better known as the Choke.

[Egaeus]

That's it, but I still don't see how that narrow opening can pull enough fuel to affect starting, how it affected the normal running of my bike, and how my choke still worked when the hole at the end of the L on the float was completely clogged.

[boltiker]

Just a suggestion. A bad o-ring seal of the L-shaped part may increase fuel flow and make the bike run "better".

[Gisser]

That's it, but I still don't see how that narrow opening can pull enough fuel to affect starting, how it affected the normal running of my bike, and how my choke still worked when the hole at the end of the L on the float was completely clogged.

But your observation was that the clogged choke was not the cause of your problem.  Synchronizing the carbs was the apparent solution:  http://gstwins.com/gsboard/index.php?topic=33403.msg372824#msg372824