Hole in Carb .

[rotten]

Pulled apart the carbs for inspection and cleaning and found this casting defect hole under in the inlet to diaphram area , any thoughts on how this would affect function ?   I'm gonna jb weld it shut it and move on  , but I wondering what possible problems this would pose if left un repaired ?

[Big Rich]

That's on the air filter side, correct?

I can't recall what that pocket is for, so it's tough to say what is underneath it..... but looking at the intake side of the carbs, at the top side of the opening, there should be a thin oval port. That's the passageway for air to help the slide move up. Is there any other hole for air to get above the slide?

[The Buddha]

It is I am pretty sure a defect, but not likely to matter ... Let me look in a carcass tomorrow.
Either case - you can plug it with JB weld or some solder and ride on.

Cool.
Buddha.

[yappahgo]

Here is the photo of that side of the carbs from the carb anatomy master thread. I don't remember paying any attention to that cavity when I was cleaning my carbs. I'm curious to find out what it's there for!



(Edit: missing closing url tag)

[Badot]

That lets air from the airbox (or your lunchbox) under the slide diaphragm... When the carb starts generating vacuum in the throat, the vacuum propagates through the holes in the bottom of your slide which takes it to the top of the diaphragm. Then you have vacuum on top, atmospheric pressure on bottom, so the slides go up, opening the carb and reducing flow rate (and hence vacuum) until the pressure becomes equalized (minus the slide spring force of course).

The hole being punched through like that will probably be negligible -- there will be slight vacuum in the throat at that point, but there's a much larger passage there to atmospheric, so it shouldn't affect your slide position any substantial amount. You may get a slight flow disturbance in the carb throat but it's not like these are precision tuned. I'd still put a dab of epoxy in for good measure though.

[rotten]

Great answers , Thanks!, I'm just gonna close it up  , and wait for my viton o-rings to show  since one flew off and was  never seen again   ..... 

[rotten]

So I studied this hole a little more - its poked into the vent line which is direct vented from the fuel bowls. 
This bike has a problem with with one of  thecylinder's fouling out , could this be the cause ?  Its possible its pulling fuel through the unintended orifice   , but i doubt it . My money is on weak spark . Regardless it sealed and curing at this point in time .

[Badot]

Hmm, maybe I was mistaken in that the punched through hole led to the throat of the carb. If it leads to the atmosphere vent channel thing on the carb (the one with a plastic tee), it would lead directly back to the airbox where the difference, again, should be negligible. (of course it would still be great if plugging the hole fixed the problem  )

[rotten]

(of course it would still be great if plugging the hole fixed the problem  )