What the heck is THIS called?

Hoo boy, are you people going to get tired of me pumping you for silly information...

Okay, I took the carb assembly off the bike, and I notice that going into the engine from this point, each hole has this long, skinny pipe thing sticking straight up, with a rubber thingie held on by a clamp. What is it, and what's it for?

Bonus question: What symptoms would you expect when one of the rubber thingies is completely missing from the tube? The right, inside carb is missing it; didn't notice until I had the carb assembly off the bike...

 

Methinks you're talking about the vaccum supply connectors.

This is where you connect a manometer (synch tool) to synchronize the carbs.

Intake #3, that you say is missing the rubber cap, is normally where the vacuum tube from the petcock connects -- this is what turns on the fuel flow when the petcock is in the "ON" position.

Symptoms would be all kinds of strange running issues as that cylinder now has a vacuum leak.

Option #1 - replace the fuel tube - it's the smaller tube on top of the main fuel tube coming out the side of the petcock -- it goes to this connector.

Option #2 - plug the vaccum connector with a plug or cork.

Good Luck!

 

Hey Mark, Altus is right on! I would however suggest getting caps for the tubes as there is less risk in ingesting cork or other material into your intake (remember, there is vacuum present behind the tubes). Another note, all of your manifolds should have this fitting with caps on them save #3. Should the tubing from your fuel petcock be cracked, do not use rubber replacement line, it will degrade and introduce contaminates into your fuel system. Get the synthetic replacement line recommended for the application. Have at and good luck Mark.

 

Duh...

Hey, at least I can skip that "where does the other end of the vacuum line go" question when I rebuild! :lol:

Thanks again, guys!