What is the release tube that hangs down below a bike?

Question

I think it's called the overflow thing, but I cleaned out the carb, started up the engine, which ran under it's own power for about 10 seconds, then died, and puked dark brown liquid out that tube.

Answer 1

Depending on the bike, it could be any number of things, but usually a vent of some type.  My bike has 2 carb vents, a carb overflow drain, an airbox drain, and another for emission-related c**p. I don't have a battery on this bike, so there isn't a vent for that.

Answer 2

I owned a Yamaha once that had three tubes

- battery vent/overflow

- Crankcase vent

- a tube coming down from the airbox (not sure what for)

Answer 3

yes battery or carb overflow to keep it from spilling over on the engine

Answer 4

Dark brown liquid would be oil.

The tube would be the crankcase breather tube.

Let us know what bike you have and where the tube attaches to.

Answer 5

battery drain.

Answer 6

It could be one of three things.  Carb overflow, battery overflow or air box drain.   If dark brown fluid is coming out it is probably an airbox drain.  Open the airbox and check if there is engine oil in it.  If there is, replace the air filter and change the oil with the proper quantity.  It may be the carb overflow (actually higly likely since you said you cleaned out the carb).  If that is the case take the carb off and clean it again.  It is probably not a battery overflow.

Answer 7

Battery acid drain, so it doesn't go on the bike and on some bikes there is a drain for if you overfill the gas tank, because gas dripping on a hot engine will catch fire.

Answer 8

Before we can properly answer, it would be handy to know what brand and make this motorcycle is!

If it is an offroad bike, then you may be having problems with more than just the carb, or gasoline.