two ports, one hose ( underside of tank )

[DavidATL]

I pulled my tank off today and found two ports on the underside and one hose on the bike. Looks like I’ll have to chose (or get a 2nd length of hose). To me, it looks like neither port was attached to the hose anyway.


Found this elsewhere on the forum:
"The forward one of the pair vents the tank. The rear one drains water from around the fuel cap."


If I keep just the single hose, which port would you recommend I connect it too? I’d chose the tank vent as a little water won’t hurt. Or does this really matter….

[Laitch]

Hang an air accumulator cup on the frame junction where the two tank ports will enter it then attach the hose to the cup. A cup costs a few dollars ordered from a BMW dealer online. Part number 16 13 2 307 467.

[Scott_]

Yea, what you don't want is to have an overfilled fuel tank letting liquid gas down that hose into the crankcase to dilute your oil......
You might try and find the other end of the hose, it might be disconnected and capped.

The "Cup" is the way to go.

[duddini]

The cup is less than $4.00, but they want $14 to deliver !!  I'm waiting to buy one until I need a couple of other items.

Bob

[Martin]

It would not be that hard to make one.
Regards Martin.

[Michael Sydney]

In the mean time run a second hose parallel to the one you have and connect both vents. better than raining fuel onto the motor. Both hosed can run to the road to carry any drips.

[DavidATL]

Hang an air accumulator cup on the frame junction where the two tank ports will enter it then attach the hose to the cup. A cup costs a few dollars ordered from a BMW dealer online. Part number 16 13 2 307 467.

Thanks for this. Didn't occur to me that there might be missing part!


Due to wiring, there's not a lot of room for the cup. It's possible that something related to the OEM alarm or aftermarket lighting (two lights are mounted on the tubes just above the front axle) might have interfered so a PO removed it. It would have been nice to have replaced the cup with dual drain lines....

[Laitch]

Didn't occur to me that there might be missing part!

It might never have been on the bike. It's development was a BMW afterthought to ease maintenance. Martin's suggestion of adding another hose should work. These hoses get routed to outlet behind the rear footpeg plate. Mount them with quick detachable fittings if you tend toward impatience and figure you'll be removing the fuel tank often. I've got two hoses on my bike—no problem.

[The Mighty Gryphon]

I believe that one of the ports is the water drain from the filler recess.  Unless the thought of a little water dripping onto the transmission keeps you awake at night, you can leave that one alone and just put the hose on the tank overflow/vent. 

[Michael Sydney]

One may be water and one fuel, but which one is which? :)
In any case the " water" one may occasionally channel spilt or overfilled fuel so better to tend to both.

[DavidATL]

Found this elsewhere on the forum:"The forward one of the pair vents the tank. The rear one drains water from around the fuel cap."

[rbm]

Take a look at this post:  http://www.motobrick.com/index.php/topic,10105.msg86113.html#msg86113

[MIbrick]

I *may* have a spare cup. If I do, and you want it, PM me your address in Atlanta and I will USPS it down to you.