Bonneville America Forums Forums Technical Forums General Tech A couple carb questions

Does anyone know for sure whether or not there is a hose connected to the float bowl vent T fitting on the modeal without EVAP, and if so does it just hang down open ended beolow the frame? Squirrel condoms.......any chance the 05's have only one of these capped hoses? I cannot for the life of me find a second one.

Daz, my bike does not have the EVAP and has three hoses coming out under the bike frame. Two with condoms, one unprotected.

Does anybody really know what time it is?

Jeez

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We have no hoses or T fitting at all on the float bowls of the non-Ca carbs. Just a nipple on the bottom of the carb float bowls and the drain screws in the bottom sides of the float bowls. We put an empty cat food can under the carbs and turn the little allen screw out. It just runs straight out of the bottom of the carbs into the can. No nothing there.

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Well, here we go again. Fact: even the exploded views show there IS a T fitting on ALL of them ! Dinqua was wrong, sorry. He's a wealt of info, but not here. We all make mistakes, but of course you immediatly figure i'm the one who's wrong and wasn't listening. Why i'm always a target no matter what i ask is beyond me, but the question still stands.....is there a hose on the non Ca models and if so does it just hang open?

And yes, i DO know what time it is. Maybe you should have asked and i'd have given it to you.

So why did you bother to ask that which you already definitively knew?

Jiminy Cricket!

This is my LAST reply to your mean spirited 3rd degree. Don't you have anything better to do?! Geez ! I do NOT, repaet NOT know whether there is a hose on the T fitting and whether it's connected to anything.THAT is what i'm asking. Had you read my last post you'd know that. Or should i say, had you retained anything other than what you need to have a go at me.

Let me see if I understand your delimma. You say that some picture shows what you seek. A fellow member says that is not so. Who is it that would answer your question and you would believe them? Simply question for the simply things in life. Breath easy brother. Ride free and safe.

To hep ya out, a hose does T round our carbs, yes the non CA models. This is a fuel hose. Our carb bowls have no hoses. Period. I don't care what your seer says. I am going to my room now.

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To hep ya out, a hose does T round our carbs, yes the non CA models. This is a fuel hose. Our carb bowls have no hoses. Period.

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Unless you mean this one

Good old Tech Vault

Yes, thats it. I can't figure why Pat said there isn't a T fitting since thats his tut ! In any case, from that tutorial it sounds as tho he eludes to the notion that it connects to something, but on a non-EVAP equipped bike i wander what. Maybe a breather filter or the like.

It connects to nothing, it is just rather difficult to put it back in position if you do pull it out. It is open at the bottom.

Thanks Larry.

Well it was simply a misunderstanding on Pat's part.. his response was that there were no vent hoses attached to the float bowls and he is correct. The vent tube is not connected to the float bowls.. it's attached to the line between the carbs. The vent tube for the float bowls is there on all models and most vent to atmosphere but I suspect on the Ca. models it will vent to a carbon or charcoal cannister.
The hose shouldn't really be plugged at any time because it's function is to let the fumes out as the as the fuel expands from the effects of heat and should allow air in as the fuel level drops in the bowls.

Actually, on the EVAP it does the same, tho via a valve that opens when you turn the ignition on. I even checked that valve when i was troubleshooting it and it works fine. But before it goes to the valve i think theres another T joint that splits it up so that another hose goes from there to the aux cannister. I looked at it for a long time trying to figure out just how it works but i can't figure it out. Doesn't matter tho.......i was just trying to figure out what i should do with the vent fitting if i decide to $hitcan the EVAP.
By the way, the float bowls themselves of course aren't physically attached to the vent, (as u said why Pat probebly said that) but apparently they vent the bowls thru a passage from where the vent tube attaches to the carbs. i found some other posts here about it and even one where someone talks about the vent hose getting clogged and his carbs overflowed out the back. So when a bike is running rich on both sides that hose should probably be a priority suspect since few other things would cause both sides to foul. It need not be fully blocked in order to run rich w/o overflowing into the airbox i suppose.

On the 80's chevys the system was kinda the same I'll bet.. they used a purge valve to direct the flow of gases to their proper places. The fuel tank and the carb bowl vents were filtered through a charcoal cannister, some to the intake manifold to be burned with the combustion process and some filter to atmosphere through the charcoal cannister. When the valve malfunctions it creates a rich condition by allowing fuel to be sucked from the float bowl into the engine. Probably the same kind of set up.. I'll have to check it out and see what i can find in the manual about it.

Is your AIR still attached? What it does is inject air into your cylinders during decel to help ignite the unburned fuel. It makes the combustion chamber hotter ( more air....more heat) to cut down the amount of raw fuel released in the atmosphere. If it were disconnected, it might run a bit rich due to the Ca. emmisions stuff...
Dunno...

The whole idea is to acheive that 14.7 to 1 air/fuel ratio as often as possible. Carbs are kind of a "close enough" approach to internal combustion.. I mean the fuel will burn when ignited but the air dictates how much and how fast it will burn before the next cycle of the engine.
The age of digital fuel injection has brought that constant closer to reality. With sensors sensing and counter counting it gives just the right amount of fuel to the cylinders with every revolution.
Carbs are too sloppy.. and we can tinker with them.. they don't like that. So before long now they'll take our precious carbs away and it will be a digitally injected world.. gone are the days of bumping the timing up to drag race... a little bit bigger jets and this sucker really rolls kinda stuff. Free flow exhaust and open air breathers a thing of the past. Alas pour Rochester.. I knew you well...

i ripped the AI off it first thing before i got the pipes. And i recall at that time having suspicions about the EVAP system because when i removed the AI i had some wierd malady i can't even remember now. But for whatever reason i came to suspect that maybe somehow removing the AI affected the EVAP system. But after i got pipes and began jetting it whatever was happening went away.

I just read up on it in the manual.. pretty cool little system actually.. it says there are two charcoal cannisters.. a primary and secondary. They basically just catch the vapors from the tank and float bowls and store them in the primary cannister untill the engine is started. Once the engine is running, the vaccuum pulls the vapors into the combustion chambers to be burned.
The switch you spoke of directs the vapors to the carbs when on and the cannisters when off.
The secondary cannister stores accumulated liquid fuel that is supposed to be drained during service.
Really basic.. very cool. Pretty uninvasive for an evap system....

That schematic is hard to understand because it doesn't seem to shiow exactly what i see on the bike. The valve i spoke of for example has one end where the hose attaches from the float vent tube and on the other end of the valve there is an unattached opening. yet i don't see that in the schematic. I tried blowing in the hose that attaches to the vent T fitting and turning the ignition on annd off, and sure enough when the ignition is on i can blow thru it and feel the air coming out the nipple on the other side. then it closes when i turn the key off. Thats why i have a hard time exatly understanding whats going on by looking at the schematic. Not just that, but there are other things that didn't seem to match on the bike. The manual shows a different system for the 790, but i wonder if there are even more variations. If you look at the OEM parts exploded view there are 2, and one is like mine and shows the valve with a hose on one end and nothing on the other, but the manual schematic doesn't show that, and mine at least doesn't have a exploded view. Cool thing about the bikebandit OEM parts exploded views is that they use dotted lines to indicate what part attaches to another. So you can see the valve is hosed at one side and open at the other. When i first noticed that unused nipple i wondered if theye was supposed to be a hose on it. The manual didn't tell me that but bthe oem parts did ! That bikebandit resource is great ! More than just part numbers and prices.......the exploded views go beyond what the manual shows by indicating what goes where.