R1100 GS tank issues

Discussion in 'GS Boxers' started by cnmjr123, Dec 3, 2020.

Tags:
  1. cnmjr123

    cnmjr123 Been here awhile

    Joined:
    Apr 30, 2020
    Oddometer:
    484
    Location:
    CT
    Hello all,
    I recently cleaned my injectors to fix a surging issue. The bike was running great with the clean injectors for about a month.

    This week, the same symptoms started again: fouled injectors again...

    I pulled the tank today to inspect the fuel screen and pump. There was a ton of sediment in the bottom of the tank and the screen was pretty gunked up. It appears the tank liner had peeled off and a bit of rusting has started.

    Should I re-line the tank or source a new one? Any advice is appreciated. 9689BC8C-F232-4218-AA66-392F78EEDD5E.jpeg F8736F1C-D859-475D-AA3A-E5AB7E2D955E.jpeg
    #1
  2. lewisjr1

    lewisjr1 Long timer

    Joined:
    Sep 26, 2008
    Oddometer:
    7,344
    Location:
    DC metro
    That 20+ y/o tank liner flake is not uncommon. Ethanol, in particular, doesn't do it well. Water accumulation when the tank is left only partially full doesn't help either.

    Many just chemically remove the OE liner and then run bare or commando - your call - for years thereafter without issue. Doing so works out better if the tank is religiously topped off for storage.

    Others reline the tank with POR products or their competitor.

    No need to source a used tank - or god forbid a new one from BMW - unless you just have to have a museum piece, or the tank has rusted holes leaking fuel.

    Me, I'd clean it out, plop in a fresh fuel filter + maybe internal lines, carefully button it all back up & ride on for another decade or more.
    #2
    eri, White Owl and cnmjr123 like this.
  3. cnmjr123

    cnmjr123 Been here awhile

    Joined:
    Apr 30, 2020
    Oddometer:
    484
    Location:
    CT
    I’ve been down the POR route with my ‘72 XS650, what a mess...

    Would a mineral spirit remove the rest of the liner?

    Is the filter screen replaceable? It’s kinda crunchy

    Thanks
    #3
  4. PeterW

    PeterW Long timer

    Joined:
    Nov 11, 2005
    Oddometer:
    5,535
    Location:
    Gold Coast
    Mineral spirit is unlikely to help with the liner.

    Load of old (but not rusty) nuts and washers or some lengths of cut up chain is the typical cleaner. Remove the fuel pump and make up a blanking plate, shake vigorously rotate , shake again, I'm sure you have the idea, main point is to get rid of all the lose flakey stuff with that.

    You can use vinegar or one of the rust conversion compounds after that but the modern POR-15 kits come with everything needed, buy a rubber bung for the filler and just follow the instructions. I have seen that used successfully on bikes recently. Personally I'd go that way because the metal tanks tend to develop leaks along the seams if the rust was bad and the tank sealers avoid that problem as well.

    The filter should be replaceable, and even if it isn't officially you'll find them on ebay for a number of bikes, not expensive so even if you get it wrong a few times it's not really an issue. Personally I'd be looking for a new fuel pump here, the one you have is unlikely to be healthy with that much crap floating around.
    #4
  5. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

    Joined:
    Feb 11, 2005
    Oddometer:
    96,714
    Location:
    Alexandria, VA
    Put a couple of handfuls of smaller washers and nut in it and shake it for a while. Dump them out and have a look. If clean, put it back together and run it. Rust, so long as stored full if stored for more than a couple of weeks, is a non-issue.
    #5
  6. lewisjr1

    lewisjr1 Long timer

    Joined:
    Sep 26, 2008
    Oddometer:
    7,344
    Location:
    DC metro
    You can definitely find & use an aftermarket sock or prefilter inside of that tank. Here's a somewhat recent post that discusses a NAPA or similar part... https://advrider.com/f/threads/2000-1150gs-tank-internals.1415475/page-2#post-38874127

    @mouthfulloflake may have pertinent part nos. handy for the 1100 model tanks. He's good like that!

    I'd refresh whatever rubber bits behind of the fuel plate that you can, in hopes of being done with it once the nylocks are (carefully) secured.

    Also, I might carefully chase the threads on those studs before installing the nuts. You don't want to bugger or snap off on of those studs. New nylocks wouldn't hurt. If you're paranoid - I am - then a very tiny dab of antiseize wouldn't hurt either.
    #6
  7. Ruizing

    Ruizing Back for more adventures Supporter

    Joined:
    Mar 11, 2006
    Oddometer:
    660
    Location:
    Just north of NYC
    +1 on everything Jim and Lewisjr said. I re-lined a tank once - about 20 years ago. I would never do it again. I have also done the handful of nuts trick to clean a tank and it worked well. As long as you are riding it regularly, and keep it full-ish in cold damp weather, you should be good to go. Beemer Boneyard is a good source for replacement hoses.
    Be VERY careful with those little studs. You don't want to break one. I just did my filter, and didn't replace the nylocks, but I did a dab of anti-seize.
    #7
  8. cnmjr123

    cnmjr123 Been here awhile

    Joined:
    Apr 30, 2020
    Oddometer:
    484
    Location:
    CT
    I appreciate the replies folks. I’ve done the nut trick on my XS, looks like I’ll need to scrounge around for the ol’ sack o nuts again. :D

    Going to make a block off plate from some aluminum soon. The bike recently had the tank internals serviced but it looks like I’ll need a new screen and filter to be safe.

    I’ll clean the fuel level contacts too while I’m in there, my “top bar” never illuminates with a full tank.

    When I replace the flange, does the o-ring seal it completely? The previous owner had different sized nuts, different washers, and some gasket sealer on there...:confused
    #8
  9. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

    Joined:
    Feb 11, 2005
    Oddometer:
    96,714
    Location:
    Alexandria, VA
    Yes, the O-ring seals fine. Get a new one with the filter from https://www.beemerboneyard.com/fuelfilters.html
    #9
  10. GS Addict

    GS Addict Pepperfool Supporter

    Joined:
    Sep 24, 2006
    Oddometer:
    8,172
    Location:
    Sunshine Coast B.C.
    Drywall screws work well to strip peeling liner and rust
    #10
    JimVonBaden likes this.
  11. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

    Joined:
    Feb 11, 2005
    Oddometer:
    96,714
    Location:
    Alexandria, VA
    I never tried that, but makes sense. They have sharp edges, but at light enough not to make a ding in the tank!
    #11
  12. cnmjr123

    cnmjr123 Been here awhile

    Joined:
    Apr 30, 2020
    Oddometer:
    484
    Location:
    CT
    Ordered filters, o-rings, clamps, hose and vacuum clamps from BBY.

    Let the next project begin!
    #12
    JimVonBaden likes this.
  13. Jshbrwr

    Jshbrwr Been here awhile

    Joined:
    Feb 7, 2014
    Oddometer:
    165
    Location:
    Alabama
    Hey folks, a little behind on this but I’m running into the same issue on my 11GS and am leaning towards avoiding the POR-15 and just cleaning things out and replacing the filter/pump and gaskets. Dumb question, when doing the drywall screws/nuts trick should there be any liquid at all in there, or just shake it “dry” and rinse out after? Just trying to think of it step by step.

    Also, what about the two hoses that remain in the tank after I removed the fuel pump assembly…? Where exactly do they go ? I feel like they should be secured or removed when I shake the tank out…thanks

    IMG_8795.jpg
    #13
  14. PaulBarton

    PaulBarton Long timer Supporter

    Joined:
    Apr 14, 2015
    Oddometer:
    4,142
    Location:
    Seattle
    Those are the vent and overflow lines. They run up to the tank cap. One connects to the anti-tip spill float and the other to the vent hole. They should be removed otherwise they would rendered useless by the drywall screws.
    #14
    Jshbrwr likes this.
  15. lewisjr1

    lewisjr1 Long timer

    Joined:
    Sep 26, 2008
    Oddometer:
    7,344
    Location:
    DC metro
    Acetone or MEK (Methyl ethyl ketone) if you're hardy. But both put off lots of gas, so only use in an open area. Paint stripping products will usually contain one chemical or the other.

    You can try vinegar if you're a tree hugger; nothing wrong with that.

    I'd also carefully clean the threads on those studs using a wire brush. Extra credit for chasing them with a fresh bolt. You do not want to damage those threads, and you absolutely don't want to snap one of the studs.
    #15
    Jshbrwr likes this.
  16. sperz1

    sperz1 Lame Adventurer Supporter

    Joined:
    Mar 10, 2010
    Oddometer:
    2,025
    Location:
    Pensacola, Fl
    I had to do the same repair on my 92 r100gs. I used a length of chain and water. Shake that thing and rinse, using compressed air between rinses to make sure the larger flakes were all out. Rinse and repeat until everything is clean. The final rinse was with mineral spirits to get out the remaining water and then left to air dry.

    Once done with that I used some eco friendly rust proofer I found at an auto shop. 2 years later and it's still fine.
    #16
  17. Jshbrwr

    Jshbrwr Been here awhile

    Joined:
    Feb 7, 2014
    Oddometer:
    165
    Location:
    Alabama
    Thanks Sperz…I like the chain idea since there’s only one piece and it’s not likely to leave anything behind!
    #17
    sperz1 likes this.
  18. Tallguy 1

    Tallguy 1 Been here awhile

    Joined:
    Jun 9, 2020
    Oddometer:
    102
    Location:
    east sf bay area
    A trick I leaned from an antique motorcycle friend is to buy cheap toilet bowl cleaner at the Dollar Store and use that as a cleaning agent inside the tank. I assumed this stuff was caustic soda but reading the label I find it is "sulfamic acid." (you can Google that) I bought 4 bottles for $1 each and only used 2. The brand name on the bottle is "The Works" Classic Clean Toilet Bowl Cleaner. This stuff disolved my rust in a few hours and I imagine it would eat away factory tank lining also but probably wouldn't touch aftermarket rubberized linings. I also used nuts/bolts. Replace internal tank vent hoses with "SUBMERSIBLE" fuel line available at auto part store or at an outdoor power product store as it is used inside gas tanks of mowers, tillers etc. Good Luck, Mike. Personally, I would replace the fuel pump.
    #18
  19. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    33,980
    Location:
    The Berkeley of Arkansas
    The submersible fuel lines in the tank needs to be pressure rated ( I am Not talking about the vent lines)

    SAE30R10 is the standard
    100 psi rated
    The proper hose is about $25 per foot
    If you put the wrong stuff in there you will be back in the tank soon with a mess to clean up.
    #19
  20. lewisjr1

    lewisjr1 Long timer

    Joined:
    Sep 26, 2008
    Oddometer:
    7,344
    Location:
    DC metro
    Gates makes a fuel injection rated, submersible hose with a 5/16" ID that is proven to work inside of BMW 11x0 fuel tanks. It is often available at decent auto part stores, though you can't count on the counter monkey to know about it - caveat emptor. Specific hose numbers are available in prior threads.

    BBY also sells a suitable hose length for a fair price. EME may as well. BMW certainly does. Regardless, it's pricey stuff. Luckily it a lasts long time.

    I had a Dallas dealership install an incorrect hose during a warranty pump replacement. The wrong hose took out the replacement pump in about a year due to ethanol related hose deterioration, possibly coupled with old hose. That was a frustrating experience, esp. because I had moved far away from that dealership.
    #20