Stupid ?

Discussion in 'Airheads' started by CENTURION, Sep 27, 2013.

  1. CENTURION

    CENTURION Be humble brother!

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    I rebuilt my carbs and put them back on and can't seem to get the 90 degree air tubes back on without nearly destroying them. Tried leaving all clamps loose and working each coupling a little at a time but no luck. Is there a trick to this? Did a search but couldn't find anything.
    Thanks, Bill
    #1
  2. Beater

    Beater The Bavarian Butcher

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    Take the carbs off, and put the tube on the carb ... then install carb and tube together. Head side first, then airbox side.

    :thumb
    #2
  3. More_Miles

    More_Miles ├╝ber-n00b

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    Slide the rubber coupling that goes between the 90 degree tube and the airbox on until the plastic tube is flush with the top of the rubber. Install on the carburetor. Slide the rubber coupling back up over the connector in the airbox, joining the two. Tighten clamps. Done.

    Stumbled on this trick by accident!
    #3
  4. blaine.hale

    blaine.hale Long timer

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    I always end up doing what Fred mentioned but don't snug it all the way on to the carb so I can kind of bend everything and get it all at an angle then literally roll it all together and it pops right into place. The bend of the elbow should face down, then you roll it up to its home position and it all should seat in.
    Kind of a hard thing to explain w/o a video demo.
    #4
  5. Plaka

    Plaka Brevis illi vita est

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    The /6 has a right tube and a left tube. They are not the same. Each tube has a carb end and an airbox end. Those are also not the same (and that's the one that bit me last)
    #5
  6. blaine.hale

    blaine.hale Long timer

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    The fluted side of the tube typically goes up, against the airbox, not down near the carb...just to add to your statement.
    #6
  7. kadesean

    kadesean eyesuck

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    Yes, double check your orientation. I had a helluva time installing them backwards :rofl
    #7
  8. Cordless

    Cordless Two Wheel Addict

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    If you'd like a second pair of hands let me know. I've got lots of time comin up and lots of experience putting those troublesome carbs together.
    #8
  9. disston

    disston ShadeTreeExpert

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    I had always had trouble fitting the carb tubes when I had them off. Then one day I took all my carb tubes outside and took the tubes off the bike that were on and started from scratch. Of course you need a small pile of carb tubes to do this. But I chose a suitable tube for each side and have had nicely fitted carb tubes since then.

    Don't know which model tubes I ended up with but I had a pile of 8 or 9 total and all of them were different.

    If you were here in Maryland I'd let you try all of my spares to see if you could find a pair that works. Maybe a Beemer Wrecking Yard or some of the larger Beemer mechanics might let you rummage their spares?
    #9
  10. CENTURION

    CENTURION Be humble brother!

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    Wow, thanks for all the responses and great ideas, should be able to get them back on. Thanks Cordell, Ill try some of these ideas and let you know how it goes, need to get together and see whats happening in your shop.
    Thanks, Bill
    #10
  11. Plaka

    Plaka Brevis illi vita est

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    On the /5 which should have the same airbox as you have, the plastic carb tubes were sensitive about getting a lip tucked under at the airbox. If you didn't notice, it would take a set and was impossible to straiten. I don't recall it having rubber up there.

    Anyway the easy way to get it together was to loosen the carb to head clamps, tip the carb outwards and at an angle, then start the tube on both the carb and airbox at the same time. As you pivot the carb back and rotate the tube with the other hand, it all comes together. Once you get it once it's easy forever.

    look down on the engine from the top. One cylinder is farther back. That side gets the shorter tube. The holes in the airbox are symmetrical, the jugs on the motor are not.

    On the later square air boxes, the holes are offset to match the motor and both air tubes are the same--but not the same as the early style.

    When you have the tubes off, stick two finger up the hole and feel for the long skinny bolt clamping the airbox halves. That's the easy way to put that bolt in.
    #11
  12. bmwhacker

    bmwhacker Still on 3 wheels

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    YA....
    I bought some replacement tubes a few years ago and they just wouldn't fit my R100S engine..
    Lined up my collection of 8 (or so) different R/L tubes, all from 70's models, and found that nearly all had subtle differences. Finally ended up with an older pair that would fit.
    #12
  13. Plaka

    Plaka Brevis illi vita est

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    I(t can be worth putting the air tube on, then the carb on that, then see how the carb to head rubber is breaking. Old carb to head rubber has taken a set. Adjusting the carb in it for a slight difference on the other side of the carb won't happen. Works with fresh rubber.

    I believe there were several different sized heads but I think the differences were taken up in the carb to head rubber, and it was small. Anton would know exactly.
    #13