Vacuum line

[Westone]

Hi,
I was poking around under the left side fairing panel of my '88 K75, and noticed a disconnected vacuum line under the gas tank for which I am not able to find a connection. It is small diameter, about a foot long, and originates on the top of the engine block near the front in the center right behind the front edge of the block. It makes a bit of an S up to just beneath the tank. It was just sitting there in need of a connection I looked and felt around under the tank and on top of the air box for a connection and could not find one. However it's crowded in there and could be easy to miss.

Can anyone tell me the purpose of this line and where it is intended to go?

[TimTyler]

Sounds like the fuel tank overflow drain hose.

Wait - You mean it's connected to the engine block?

[Chaos]

go ahead a plug it shut.  They used to vent the gas tank into the crankcase but the crankcase ventilation could cause overly rich conditions under certain conditions.  Whoever disconnected yours should have removed the tube and put a cap on the block.  No harm done.

[Grim]

And there is a little mod you need to do thats cheap. Its call a " air accumulator cup"  Eventually the tank may puke some fuel. This post explains a way to make sure it doesn't end up on the engine. 
http://www.motobrick.com/index.php/topic,989.msg3961.html#msg3961

[Westone]

Thanks for the info.

[Westone]

Just ordered the air accumulator cup, dirt cheap at $2.26. The associated drain hose was more than that. I pulled the tank all the way off this past weekend and found neither of the outlets on the back of the tank had been plugged nor had a line attached to them.

This may be a dumb question, but where can I get a rubber cap small enough to plug the small diameter outlet on the engine block? I can put a piece of small fuel or vacuum line on it, then plug the line. A rubber cap would be a more elegant solution if available in the correct size.

[Scott_]

This may be a dumb question, but where can I get a rubber cap small enough to plug the small diameter outlet on the engine block? I can put a piece of small fuel or vacuum line on it, then plug the line. A rubber cap would be a more elegant solution if available in the correct size.

Auto parts store.