BMW r65 richness problem

Discussion in 'Old's Cool' started by bowerbird, Oct 20, 2008.

  1. bpeckm

    bpeckm Grin!

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    I will refer you back to post #5...it is hard to get a consistent test of the actual amount of fuel, but if you gently lift and lower the floats, you can see whether they are shutting of, and opening, properly.

    Ideally, the fuel should shut off when the float tops are parallel to the carb. If it shuts off below that (too soon) you may run lean, if it doesn't shut off til later, the bike will run rich.

    :lol3
    #21
  2. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    Again, I stand by my earlier statement. CV carbs --- out = rich, in = lean. On the CV carbs, it's the fuel that's being metered, not the air. Unlike the older Bing slide carbs (on my R50/2), which does the opposite.

    Can anyone else chime in and confirm?
    #22
  3. bowerbird

    bowerbird BMW R65

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    I have a cutaway illustration that looks to agree with you. (out=rich)
    #23
  4. Velvet Elvis

    Velvet Elvis mild mannered adventurer

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    4 out of 5 dentists agree. The Bing CV carbs mixture screws turn in for lean, out for rich. :D
    #24
  5. bpeckm

    bpeckm Grin!

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    Well, I finally got to where my Bing book is physically, and had a chance to look up whether the CV idle adjustment is air or fuel...

    And I stand CORRECTED, you 4 out of 5 dentists, Velvet Elvis, Bowerbird, Opposedcylinderjunkie are absolutely CORRECT. I learned something today.... I guess I just turn 'em in or out to where they work best, and owning two bikes with slide carbs, where the screw is the air volume screw, well........ sorry for the confusion.

    According to the Bible of Bing, Chapter and Verse (actually page 8):

    Attached Files:

    #25
  6. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    I also have that Bing Bible, and it's a Godsend for us shade-tree mechanics! :thumb
    #26
  7. Beemerboff

    Beemerboff Long timer

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    The Bing book says out for richer , but if you tune it with Colortune plugs you will find it round the other way.

    Bing got it wrong. And they sell Colortunes.

    And , for what its worth , I found the mixture was right and the bike ran best just of the point where it starts to to stumble when screwing it screw in.

    They are not orphans here - the guy who wrote the Ohlins adjustment manual doesnt know that the adjuster on the bottom sets compression and rebound at the same - he thinks it does rebound only.
    #27
  8. victor850r

    victor850r n00b

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    HELP¡¡
    i need to know how to timing the BMW r65 1981 does anybody can showme a link where i could find the procedure?
    #28
  9. Beemerboff

    Beemerboff Long timer

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    Find a decent hill on a quiet road somewhere, do a few test runs up the hill, pick a point near the bottom and go past it it at say 60 km in fourth, then gas it as hard as you can the another point at the crest of the hill, and note your speed.

    Remove the front cover , slacken the Bean can, start the engine and turn the bean can slightly either way till you get the fastest tickover, then turn it clockwise to the point where the revs just start to fall. Mark that point on the bean can.

    Go back to the test hill and do another run. Hopefully it will be faster than before, but turn the bean can SLIGHTLY anti clockwise, and do another run.
    If it is faster repeat the process until there is no improvement, then reverse the process, turning the can clockwise slightly until the performance just starts to drop.

    Then get a timing light, and see where the timing mark on the flywheel has ended up - with twin plugs and 1000cc barrels and pistons in 800 cc heads I ended up around 26 degrees advance, so I could just see the mark in the bottom of the hole.

    Or have a dyno guy set the timing on his machine, just tell him you are more interested in pick up between 3000 and 6000 revs than peak horsepower and you will get something that works.

    There is a mark on the flywheel which will give you an approximate setting, which will get you to the dyno, but your best position can vary 3 degrees either side of that mark.
    #29