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Fuel dripping from overflow line

A

AzGnome

Guest
Hey guys, I need some direction, hopefully someone can help shed some light. I have fuel dripping from overflow line on right side just above the throttlebodie. Noticed Friday, not dripping much, but this morning when I got to workit is dripping a lot . Thought Friday that I had fueled too much, but after 50+ miles to work this morning it shouldn't be over full. Any suggestions? Thank you for your time and help. 94 r1100 rs 83,447 miles.
 
Sounds like your Quick Disconnects are leaking, or maybe a vent line inside the tank. If it's the QDs take care of it soon, they could fail catastrophically.
 
Fuel filter bypassed tank on outside, right side

Is that comment indicating that you found the source of the leak or that you installed a fuel filter in place of the QD that didn't come on your bike ayway?

I'm assuming you or a previous owner shortened the vent and water drain lines if they terminate above the throttle body instead of near the right peg or in the carbon canister.

If that is the case and fuel is dripping out of one of those two lines, you are pretty much looking at either a failed vent / drain line (hose) in the tank or a failed vent tube at the fill neck, or maybe a failed nipple at the fuel pump plate. Hopefully it is just the hoses or maybe the fill neck as those are cheap.

If you need the fill neck or pump plate, I can make you a deal on parts from my '96.
 
Have not found the cause, yet. external filter mode done by previous owner. Here is a picture, the tube has a hex bolt in it to keep the fuel from dripping all over. Will start pulling the tank off tomorrow.
 

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Have not found the cause, yet. external filter mode done by previous owner. Here is a picture, the tube has a hex bolt in it to keep the fuel from dripping all over. Will start pulling the tank off tomorrow.
A hexbolt hardly qualifies as a plug, the fuel just follows the threads.
My question is where does that hose lead to and why is it so clumsily plugged.
BTW you should install proper fuel injection claps on the fuel filter, gear clamps are not designed to be used on high pressure fuel hoses
 
Broken hose?

As rxcrider mentioned, the overflow hoses should be long and run down by the RH front footpeg.

My hoses are the correct length, but I found problem on my RS with the internal hoses. The internal hoses run from the fuel filter/pump mounting plate to the gas cap assembly. In place of the original hose clamps, the PO used twisted wire to hold the hoses on the fuel cap assembly. Needless to say, the hoses broken at the fuel cap, and fell down into the tank. This created a drain, so that gas would run out the overflow hoses onto the ground whenever I filled up the tank.:banghead

So for the lack of two $1 hose clamps, I lost an untold amount of gasoline until I fixed the issue.
All recite the old, but true saying, "the cheapest thing on a BMW motorcycle is the rider".

Before pulling the gas tank, I'd take off the gas cap assembly and see if the internal hoses are connected properly. I'd also lengthen the external vent hoses. You'll still probably have to pull the tank to fix it, but at least you'll know if that's the issue.
 
Mine did this after I had replace by fuel filter inside the tank. I got it all reassembled and went and filled the tank. Started slow but kept dripping for 2 days until I could drain the tank. (Good fun, lifting a nearly full GS tank btw)

I replaced all my internal vent lines, fuel lines and clamps while I had it apart the second time. No more dripping after that. I suspect I cracked one of the 17yr old vent lines when I did my fuel filter even though I never did find a big crack in the old lines.

Do you still have both drain lines in the tank with the external filter? Overflow line and tank filler neck drain?
 
Rubber lines inside the tank

Your more than likely looking at rotted or just plain worn out rubber VENT lines inside the gas tank. Your going to have to drain your tank, take it off the bike and pull the filler and fuel pump mount plate off it to get at and replace the vent lines. While your in there make sure the other rubber lines are good and absolutely make sure all the metal parts are good too. A bolt is not a very good way to stop the leak.
 
Have not found the cause, yet. external filter mode done by previous owner. Here is a picture, the tube has a hex bolt in it to keep the fuel from dripping all over. Will start pulling the tank off tomorrow.

Those aren't the proper type hose clamps. Worm clamps shouldn't be used for FI applications. Get the proper FI clamps from the auto parts store, or replace with OEM Oetiker clamps.
 
Separate but related question....

How imperative is it that I replace the original quick disconnects on my 1100S ('03 with 40k km)? Not sure that they've ever been disconnected.

Apologies for partial thead jack...
 
The hose clamps on the filter have been fine for 20,000 miles thanks. The hex bolt/zip tie was a MacGyver fix, all I had on Hand and it seemed to work to get me home. Thanks for the advice, will Pull the Cap assembly, Tank and replace all hoses in Question.
 
How imperative is it that I replace the original quick disconnects on my 1100S ('03 with 40k km)? Not sure that they've ever been disconnected.

Apologies for partial thead jack...

If you carry marshmallow's and a stick to roast them, don't worry about it......

Seriously, they are known to fail without being disturbed. The plastic just cracks. Gas flowing over a hot motor is not a good thing.
Beemerboneyard has the correct replacements.
 
I bought the Beemer Boneyard kit and replaced mine a couple months back. The kit is great, everything you need. The clamps are large and with the screw mechanism you may find one clamp contacting an adjacent hose so take care locating them.

Getting the old Oetiker clamps off isn't easy. Have some good strong cutting pliers. In my case, the old plastic parts were very attached to the hose which had formed to their shape making it tough to get them out--patience. The new QDs went right in but the set of the old hose made it imperative that the clamps were fully tightened. In hindsight I probably should have replaced the hose, but it has turned out alright. Lastly the short hoses connect to the fuel pressure regulator which is plastic. I was warned to take care and not break the plastic parts.

In principle this is an easy job but may take longer than you'd expect. That said the peace of mind, with it done, is terrific and I'm glad I did.
RB
 
Bob and Roger,
Thanks for your input. I'll order up the Beemer Boneyard stuff today and, while I wait for them to arrive, buy a bag of marshmallows just in case. :thumb
 
Vent hose fuel dripping FIXED

So I had the same issue on my 94 R1100 RSL. Fuel started dripping slowly from the vent tube after I parked the bike, at first I thought this was normal (duh). It is obviously not normal. After reading this thread, I removed the gas cap filler port from the fuel tank to take a look around. I am pretty sure the overflow and vent tubes were original, because without too much effort one of them just deteriorated and broke off from the the bottom of the tank.
I went to O'Reilly's Auto parts and bought two 2' pieces of fuel line hose. The hoses are 5mm interior diameter, but the closest I could find was 3/16" (which is 4.8 mm) and that worked perfectly. I bought 4 small hose clamps as well. I removed the fuel tank, removed the fuel filter plate on the bottom/side of the fuel tank and that is where if found the problem. Both hoses had deteriorated and were the cause of the leak..I replaced them, and viola! No leak. It was a pretty easy fix. Thanks forum!
 
I went to O'Reilly's Auto parts and bought two 2' pieces of fuel line hose. The hoses are 5mm interior diameter, but the closest I could find was 3/16" (which is 4.8 mm) and that worked perfectly.

Odds are that hose is not rated for immersion in fuel, rather only to contain fuel. Did you check that?
 
How imperative is it that I replace the original quick disconnects on my 1100S ('03 with 40k km)? Not sure that they've ever been disconnected.

Apologies for partial thead jack...

There are some little tiny o rings in there that have been immersed in gas for 20 years, so it gets a little more imperative every day, imho.

You don’t want a fuel leak in your garage.
 
Not just the O-rings, but on the earlier bikes (at least), some of the innards were plastic.
I've seen broken ones, and a couple that broke during careful re-mating.
Nuke with extreme prejudice!
 
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