Carb Vents

[Sgriger534]

i swapped out my stock airbox with some pod filters. My question is what do i do with the nipples for the bowl vents?

[dbeardslee]

I just ran my vent lines up under the tank and kind of left them hanging there. Some members put little filters over the ends of the lines to keep bugs and other foreign debris out, but be careful what kind of filters you use. I put some lawn mower fuel filters on mine, and they had paper elements inside that don't like water. After a while just the moisture in the air was enough to plug them up. When the vents get plugged, the bowls overflow. I wouldn't take the rubber lines off the 'T's - at a minimum I would leave them on. I've been running mine like that for about two years and haven't had a problem.

[TADracer]

The wind stream on the ends of the vent tubes can cause variations in the bowl pressure which should be near the barometric pressure on these CV carbs. If you get any positive pressure in the bowl then it can put you into a rich condition as it is acting to push fuel through the system. I do not remember how they hook up in a stock air cleaner box since mine is long gone but I seem to remember they end up in a tube that is right behind the carb bells. This would make the vent tube ends in an ever so slight low pressure situation that would draw out bowl fumes and burn them but not enough to affect the fuel in the bowls.

It works good if the vent lines run up under the tank so they are out of the windstream while moving. A small air filter on the vent lines accomplishes the same thing but whatever you do make sure they are never allowed to become plugged up.

[the108penguins]

I don't mean to hijack the thread but where are the bowl vents located? I got my bike with no filter whatsoever but I've heard them mentioned several times.

[John]

On your carbs, assuming they are the correct ones for a 79, there will be a second set of rubberized T fittings between #1&2, and 3&4 carbs, and they will be above the fuel inlet T fittings between the same sets of carbs. If you have 80-81 carbs, then the bowl vents will be on the intake bell of the carbs. If you study the carb body carefully, you can follow all those little passageways that are in the carb body and learn their path.

[the108penguins]

oh well there's no T's in between my carbs other than the fuel T's so I suppose that could be why I'm having so much trouble tuning these darn things. Thanks

[DGXSER]

If they look identical to the ones being worked on in THIS thread, then they are the later style. These are the ones John stated have four holes in the inlet bell, one of which being the vent.

[John]

Check the rubbers on your pods. I'd be willing to bet that there is a ridge/shoulder inside the rubbers boots that is blocking the vents and other air inlet orifices. It is a common problem with some K&N knock offs. Do a search for pod filters and you should find a lot of info on this subject.