1150GS - noisy fuel pump/spluttering at half tank

[everycredit]

Originally Posted by Jim Moore

I highly recommend you get rid of your canister and vent the tank line to the atmosphere.

I have no canister and my fuel system is working flawlessly (sans canister).

[roger 04 rt]

Originally Posted by everycredit

I have no canister and my fuel system is working flawlessly (sans canister).

You're going to have to open up your tank and look.

[Jim Moore]

Originally Posted by everycredit

I have no canister and my fuel system is working flawlessly (sans canister).

Well, it's not working flawlessly. Something is creating a vaccuum in your tank. Since you have no canister I'll bet your vent line that used to go to the canister is pinched or clogged. Those lines are pretty easy to check, and easy to replace if there is a problem.

[Steve W.]

When I did mine I used the fuel line from euro motoelectrics. It's corrugated nylon and will make the bend. I use one piece to the outlet replacing the filter and the U. Here's the link hhttp://www.euromotoelectrics.com/BMW...fp-hosekit.htm
I put the filter outside a long time ago.
Cheers
Steve

[roger 04 rt]

Originally Posted by Jim Moore

Well, it's not working flawlessly. Something is creating a vaccuum in your tank. Since you have no canister I'll bet your vent line that used to go to the canister is pinched or clogged. Those lines are pretty easy to check, and easy to replace if there is a problem.

Yup, but at this point there are 34 replies and ideas for Flys Lo. Seems like he's got plenty to work with when he eventually gets around to opening his toolbox.

[vintagerider]

Roger, great pics. References to the fuel spider are numerous. Rarely depicted are the invasive tendrils of its web concealed within the system. If evap lines seem clear, then one can open the seams on the evap kanister to check for egg sacks. Three grams of shaved naptha inside old tea bag taped to the throttle plate during storage may discourage nesting in the first place.

[def]

Originally Posted by mouthfulloflake

I cant claim the idea, someone else on here did it, and I copied the idea!

nice brake bender tool, and a 36" section of hard line was about $15, so cheaper than the bmw part, should last at least as long ( likely longer) and I got a brake tool to boot!

there was enough hard line left over to bend a few more if I can find it in my mess of a garage Ill bend you up a U and send it to you.

I would be forever in your debt. But, maybe we can save some postage...I do get to Branson from time to time and that's not too far from NW Arkansas ....say Rogers, Bentonville? About 80 miles....and the ride would be very picturesque. All I would have to do is avoid all the Wal-Mart trucks.

Wow...Bentonville is nothing but Wal-Mart trucks every where and that was from my last travels there, about 25 years ago...its even bigger now, I'm sure.

[everycredit]

Originally Posted by roger 04 rt

You're going to have to open up your tank and look.

Originally Posted by Jim Moore

Well, it's not working flawlessly. Something is creating a vaccuum in your tank. Since you have no canister I'll bet your vent line that used to go to the canister is pinched or clogged. Those lines are pretty easy to check, and easy to replace if there is a problem.

No, it's fine.

[vintagerider]

Liz and Roger have good advice. The fuel system isn't that complicated. Those who take the time to disassemble, clean and inspect are rewarded. The OPD (overflow protection device) is combined with the tank vent which in turn may incorporate EVAP (kanister). Washing the tank isn't hard. I use warm soapy water followed by alcohol rinse. Several plumbing mods are possible. Newbies: review list of precautions before you begin i.e do not strip the tank studs. It never pays to do a partial tank service. All the ports need to be cleaned, pump impeller fins checked ect.

Out here our fuel spiders are venomous; maybe not for your region. Discuss any external fuel filter mods with Def. Apparently some fella in N Carolina burned down the drive-in then the conflagulation spread to the mayor's house. I put my filters in the steer head hollow, great for me but too many are gonna run the hose close to the exhaust. It's kinda hard to see where your going at 70 mph with a fireball up front and your groin on fire.

[Flys Lo]

Thanks for all the further responses. Hopefully the parts will be here from Beemer Boneyard early next week, so the following weekend I should be able to take the tank off and go to town. Based on what I have read here, it sounds like it is one of the lines in the tank probably has a hairline crack, and when the fuel gets down to a certain level (i.e. the fuel line is no longer submerged), it gets air in the line, and after that, the fuel pump has to work a lot harder to maintain pressure, hence the increased noise.

That's all an educated guess anyway.

Still, a good opportunity to replace the fuel pump/everything else anyway.

[mouthfulloflake]

Just let me know when you are in Branson!

Originally Posted by def

I would be forever in your debt. But, maybe we can save some postage...I do get to Branson from time to time and that's not too far from NW Arkansas ....say Rogers, Bentonville? About 80 miles....and the ride would be very picturesque. All I would have to do is avoid all the Wal-Mart trucks.

Wow...Bentonville is nothing but Wal-Mart trucks every where and that was from my last travels there, about 25 years ago...its even bigger now, I'm sure.

[vintagerider]

tips that might help:
soak threads enzymatic rust reformer; the small diameter lines should be re-used as they carry no pressure; the small clamps pop open on the pump plate- do not cut them; withdraw the pump plate and strip it bare.

Pop off the float arm- it and the filter need to be off to svc the wiper on the float which is cleaned w/new no.2 pencil erasure.

May have to rig up new float end stops w/ bit of hose zip tied to plate. Clean the points and adj the float tension by bending the L bracket which receives float arm, in or out.

Float arm should move on its own with slight resistance.

Use a stiff wire and solvent to clean out all ports, particularly OPD/tank vent in filler neck and filler neck water drain.

Insulation may be gone on pump wiring, replace with ptfe or other submersible wire.. clean and tighten ground.

Note the large electrical bulked fitting on pump plate. There is a spring retainer which compresses an o-ring seal which you can not see. In some cases this may have failed or begun to fail. If there was evidence of leaking at the bulkhead then the pump plate needs to be replaced. Sometimes the concealed o-ring will leak if the pump plate has been left dry for a while than it may slowly re-seal after filling tank. To repair the bulkhead leak one would need to locate a new crimp ring and de-solder to remove bulkhead fitting to replace o-ring (Viton).

++ When refitting the plump plate, index the flat spot to the front tank mount U's. The spring type small tube clamps are pita to re-fit. Do not use screw clamps because they will interfere with the seating of the flange to the tank. I use hd grade nylon ty-wraps.

++ Hold a nut driver between thumb and index finger to very lightly seat the retaining nuts. It is very easy to snap off the tank studs. I use a dry Viton big o-ring in U.S. size. Easy to set if the tank is on its side and empty.

other--The float arm can not be replaced once you have re-installed the filter! . Old hose should be cut off so you do not snap off the pump outlet. It is easy to knock the pump pressure release valve retaining clip off oem vdo pumps. Make sure the ball bearing and spring are in place.

The fuel suction screen should always be replaced - use the cheap paper ones, index with fuel return outlet so that it does not interfere with float arm. Ignore other posts telling you to bend the float arm. If all the fittings are clean and tight and tension of points to gauge is tight then the gauge will work fine. The hair spring wire needs to be placed back in the vdo circuit board retainer.

On early 1100 filler neck the old OPD device looks like an oval float. If it won't stay connected to the filler neck tube then can upgrade filler neck to 1150 type. The old filler o-ring can be re-used if it is left to shrink back down.

[roger 04 rt]

I'm still wondering about fuel pump plate orientation and some kind of obstruction in the vent system. Take special not on both those items. Since all the hoses are on the pressurized since of the tank, cracks there (and you may well find them) would not be sensitive to fuel level.

One other thing you could look at is some obstruction at the anti tip valve. Mine was mounted in the wrong orientation.

The good news is by working at this slowly you are very likely to find the cause.

[Flys Lo]

Thanks for all of your input.
Finally was able to get up to the farm this weekend with the bike and work on it.
Pulled the tank, drained it, rinsed it with some fuel and drained it again (didn't have the time to wash it with water and let it dry thoroughly)

Prior to the job I had purchased the replacement (non OEM) fuel pump kit from Beemer Boneyard, I had also purchased 1' of high pressure submersible fuel line, and 1' of standard high pressure fuel line. I had a few submersible fuel connectors lying around that I used on this job as well.

I removed the existing pump, filter and in-tank lines from the fuel sender.
Cleaned the swipe for the fuel guage with ear buds (Q-tips for the seppos) that were covered in contact cleaner.
I decided while I was doing this, I may as well mount the filter externally - so future filter changes won't be the pain in the arse, remove the tank, have 6 beers and swear a lot kind of jobs...

So I replaced the filter and the 2 fuel hoses connected to it, with an 8" length of the submersible line... the bend at the top of it was a bit too tight for my preference, but so much that it has kinked the line.
Fitted the new pump, other submersible hose and filter sock.
Installed the whole assembly back in the fuel tank.
Removed the external fuel line on the bike (not the return line!).
Cut 2 short sections of the new external fuel line, with the fuel filter in between them and zip tied the fuel filter to frame about where the electrical connector for the fuel tank is located.
Got some contact cleaner, and one of the little brushes you can get at your dentist for cleaning in between your teeth, and cleaned the corrosion off the electrical connector for the tank... Covered the connectors with some carbon grease.

Refitted the fuel tank and plumbed it all back in. Started it up - fuel gauge is fine. Filled it back up with fuel. I will need to wait till it gets down till half a tank to see if it is still making the noise/spluttering, but hopefully not. I'll let you know if it does/doesn't tomorrow.

Took it for a quick spin up to a bit over 200 (~125mph) to see if the bend in the fuel line in tank was starving it of fuel - didn't seem so.

I also had to reset the ABS system while the seat was off, as the bastard mechanic I had taken the bike to to get serviced last f'd up the rear ABS sensor (got a used one, and had to reset it)... serves me right for being lazy and not doing it all myself.


Sorry for no pictures, was in a bloody rush to get the job done before it hit 35 (~95 F) outside.

[def]

Originally Posted by Flys Lo

Took it for a quick spin up to a bit over 200 (~125mph) to see if the bend in the fuel line in tank was starving it of fuel - didn't seem so.

You broke the law. If you turn yourself in, we'll go easy on you.