BMW G650X Challenge Thread Index

Discussion in 'Thumpers' started by GB, Apr 24, 2008.

  1. XallengeXccepted

    XallengeXccepted Been here awhile

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    With the issues everyone is always having with the stock cap, I really wish there was an alternative solution. At this point, I'm so fed up with mine that I might even be willing to pony up the $300 or whatever it was for the Touratech cap if it was still available.
  2. XallengeXccepted

    XallengeXccepted Been here awhile

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    Thanks, I think I'll replace my chain and sprocket with that DID X-ring now for peace of mind.
  3. keepshoveling

    keepshoveling DNF

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    http://advrider.com/index.php?threa...xchallenge-xmoto.487473/page-24#post-17432510
  4. tigrebleau

    tigrebleau Been here awhile

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    Tanks for your replies. The X-tank does empty first and fills the main tank. But I think you're right about something wrong with the main tank cap; i.e., not sealing. I'll check it carefully, and try to follow the process in the link. I guess I'll disassemble it first and take the gasket and o-ring somewhere to find replacements.
  5. XallengeXccepted

    XallengeXccepted Been here awhile

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    I just went through this exact exercise a while back because the X-tank would only draw down about half way, which is right around the time that gravity stops working. So I wasn't getting a good air seal. I never did figure out where the leak is, but suspect it is still the stock fuel cap.

    I replaced the seal with thicker gasket material, and used new O-rings, even tried doubling them up. Never solved it, so I would be very interested in what you find.

    However, in my case fuel does not leak out of the cap even when the bike is laying on its side. Found this out a couple weekends ago when my bike spent a lot of time napping on a brutal trail.
  6. jjmead1

    jjmead1 now THAT"S a bike!

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    Going to throw some pictures up, because I finally got out for a proper ride. So far this summer has been plagued by bike issues.
    Some views of Red Cone
    [​IMG]
    Fun ride up as the leaves were teasing me with change.
    [​IMG]

    [​IMG]
    Lots of mining activity created these roads
    [​IMG]

    [​IMG]
    Great day out and about. It was pleasant to have the bike running solid again.
    [​IMG]
    seasider, Dutchgit, snooker and 2 others like this.
  7. khpossum

    khpossum poster

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    First thing I did was to replace the gas cap gasket with a thicker one cut from a sheet I bought from Amazon. Worked most of the time, but not all of the the time. I also RTV'd the gas cap gasket and especially the white flange on top of the gas tank. That white flange has those screwy "wood" screws, so it can not be tightened up without messing up the threads. The RTV seems to work for 6 months to a year before it needs to be renewed. This works almost all of the time, but I still once in a while loose vacuum in the main tank, but learned to put up with it.
  8. tigrebleau

    tigrebleau Been here awhile

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    Erik Bok of Hotrod Welding in the Netherlands, maker of the auxiliary tank, was very helpful with a pic of the disassembled main tank gas cap. He advised that the cap should be fuel-tight even with the tank completely full and that the usual leakage culprit is the internal viton o-ring that seals the lock cylinder. Now, if I can find a source for that, and the flat gasket, I can solve the problem. I also have to shorten the sidestand to keep fuel away from the cap as much as possible and to keep the bike from being too-near vertical on the stand. Any info on a source for the parts appreciated.
    I'd rather not spend the $130 at BikeBandit to replace the whole cap, but If necessary I will so I can keep a full tank when the bike is in the garage.
  9. khpossum

    khpossum poster

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    I have the larger TT tank so your situation may not be quit the same. Shortening the side stand will do nothing to prevent fuel leakage most of the time. Most of the time I find the fuel level in the tank well over the fuel cap level. If things works as designed fuel will run out every time you open the main fuel tank if you have fuel left in the aux tank. And yes, that pesky little oring may need replacing. Just go to a bearing place and they most likely can fix you up with an o-ring as well. Napa may have it as well. If I remember that is where I got mine.

    Come to think of it since you have Erik's fuel tank I guess you have to use your main fuel gas cap to fill up most of the time. RTV'ing the gas cap will not work. With the TT tank I usually can fill up before the main tank starts to come into play.

    For the gas cap gasket I bought a small sheet of viton from McMasterCarr and cut it myself. It was just a hair thicker then stock.

    YMMV
  10. Erik RS

    Erik RS Three Wheel Maniac

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    I take it it would work the same with the Xtank :D
    But there wouldn't be much use for it being extra would there? :lol3

    My experience is that the majority of main caps give no problem (at least from the reports I get), but when they do it's often a mystery to solve even though it's not exactly rocket science :dunno
  11. XallengeXccepted

    XallengeXccepted Been here awhile

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    Yeah I have done all of those things. I have cut a thicker rubber seal that seems to seal pretty well actually. And I have put new o-rings around the lock mechanism. I have put 2 in there as suggested elsewhere. Tried first with one, then two. I have also RTV'd the white breather, and pulled the check valve out. Still no go.

    The cap does not leak gas when laying on its side at this point (it used to). But I still can't get suction into my main tank from the Xtank. I'm living with it, but it's not ideal. If I run out of gas, I just hook up my air shock pump to the breather line of the XTank using an adapter for those pool/air mattress floaty valve thingies (technical term), and pressurize it. That flows the gas into the main tank.
  12. khpossum

    khpossum poster

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    That certainly is a whole lot more elegant and effective then the blow job I have had to give my tank a few times.

    KP
  13. XallengeXccepted

    XallengeXccepted Been here awhile

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    Here is the part I used for the O-rings. They are tighter than the stock ones by a smidge, which is what I was after: http://www.amazon.com/gp/product/B000MN8G92?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

    I didn't see they were a pack of 100, so bought 2. I now have 198 extra o-rings. :rofl
  14. XallengeXccepted

    XallengeXccepted Been here awhile

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    Hahaha, a few times? I'll admit it, I did have to get on my knees once. But after that I knew I needed an alternative solution as I didn't like the taste.
    keepshoveling likes this.
  15. August West

    August West Wharf Rat

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    mbogage likes this.
  16. XallengeXccepted

    XallengeXccepted Been here awhile

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    Sorry, it's just not worth the time for me to get into the o-ring distributor business. Although, I do have enough stock... :rofl
  17. keepshoveling

    keepshoveling DNF

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    Are you sure you're just not thinking big enough? Volume, my friend. Volume! http://www.hulu.com/watch/2315
  18. tbarstow

    tbarstow Two-wheelin' Fool Super Supporter

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    Your vacuum leak is where the fuel line attaches to the white tip over valve. Hanz and Franz used an odd size and shape connection that does not fit the ID of a piece of fuel line instead od a hose barb. Try some RTV around there and see what happens. Also, the gasket under the white tip over valve will crack and leak when exposed to fuel.
  19. DonM

    DonM Do-dah Do-dah Supporter

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    Share a link to this!
  20. XallengeXccepted

    XallengeXccepted Been here awhile

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    Thank you for the reply tbarstow. Man, I really hope that is it. I'll definitely try that out. I have judiciously RTV'd the gasket under the check valve already without luck. But I did not even think to pursue checking the hose connection. Cheers!