BMW r65 richness problem

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

  1. bowerbird

    bowerbird BMW R65

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    Just joined the board today. Hello all. I hope to add to all the great conversations going on here. I have a bit of a problem with an 82 BMW r65 I recently picked up on the cheap.

    It was not running well and I discovered the left side plug was bad so I replaced them both. The now starts and runs but after about a minute or two, a lot of smoke comes out of the left pipe, a little out of the right. I tried a bunch of stuff to narrow this down.

    Valve adjustment (tight now good)
    compression check (130 in each cylinder)
    timing check (good)
    new carb floats
    general carb cleaning
    I even swapped all the jets, needles and diaphrams to see if there was any way to isolate the problem

    So now I an a little lost. I don't think the carbs look bad but wonder if I could do a $70 overhaul if I don't know it will help I wonder if it is engine richness I am seeing and smelling. I think it is but am not completely sure. The next thing I'm going to do is inspect the enrichers and see if thee is anything obviously wrong.

    Has anyone here experienced something like this?
    Thanks for any advice.
    #1
  2. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    Check your left plug if it's oil or gas causing the fouling. Could be rings if it's oil.
    #2
  3. P B G

    P B G Long timer

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    would rings foul that bad and still provide 130 compression.
    #3
  4. Solo Lobo

    Solo Lobo airhead or nothing

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    My R80G/S is running 165 lbs of compression on both sides and still manages a good puff of blue smoke when starting every second or third time after sitting for a few days...

    Don't know why yet, but am going to take the top end off to inspect this winter
    #4
  5. bpeckm

    bpeckm Grin!

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    Some pointers............
    • sooty black = fuel richness
    • shiny, oily black = oil fouling, could be rings, valve guides
    First thing to check, regardless: be sure that the float is actually shutting off fuel. Do this by taking off the bowl, hold the float up manually, turn on the petcock, then slowly lower and raise it to see that the float needle is doing its job. If it does turn it off, you might try lowering the point at which it turns it off (turns it off sooner as it rises)

    If it is fuel fouling: depends on the engine speed at which you ran this test: if they are black from idle only, check the idle circuit. If they are black from regular running, check the needle and needle jet.

    Idle: the idle adjustment is idle AIR: screw it in, makes it richer, at idle ONLY.

    Mid throttle: check to see that both needles are at the same notch (presuming that the other side is "good"), that needle is not worn, that jet is in place, etc.






    and by the way.... Welcome! ... to this insane assylumm....:lol3
    #5
  6. Steptoe

    Steptoe steptoe

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    Do you know how to adjust the mixture. The mixture screw is under the carb, turn it clockwise until the engine starts to die, then back it off until it also starts to die, then screw back in until you find the sweet point.
    #6
  7. bowerbird

    bowerbird BMW R65

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    The plugs are chalky black and dry (fuel). I'm prety sure oil isn't getting into the combustion chamber. I'm still stumped. I may try getting "hotter plugs" The manual calls for Bosch W6D. The bike came with Bosh W5D plugs which are cooler. I wonder if this could make a change. Can smoke be attributed to plugs?
    #7
  8. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    No, plugs couldn't cause this. Specially a one-step change in heat range. besides, it only happens with the left side.

    As someone said, check your float height. It could be the key to your issues.
    #8
  9. bowerbird

    bowerbird BMW R65

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    thanks for the reply, I'll look at the floats furhter.

    The idle mixture screw stock setting is 3/4 turns out. Could the idle mixture come out?
    #9
  10. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    It could but after many, many turns. Try 1-1/4 turns out as your starting point, then adjust for better tickover.
    #10
  11. bpeckm

    bpeckm Grin!

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    What I tried to ask earlier:

    • Is it running rich at IDLE??
    • Or at all speeds??

    IF it is running rich at idle, try turning the air screw OUT more for a less-rich mixture. But, you may just have to pull the carb and blow out the air passages.... those are teeny tiny and you might find a passageway blocked, or partially blocked. Idle circuits are fussy....


    :lol3
    #11
  12. jdiaz

    jdiaz .

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    Did someone re-assemble a choke plate backward?
    #12
  13. Steve516

    Steve516 Guzzis R Us

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    Also check out and join in over here

    www.r65.org, for a great worldwide group of R65 fiends and all your R65 needs.
    Good luck !
    #13
  14. bowerbird

    bowerbird BMW R65

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    Thanks all. Is id rich at idle but if I rev it, smoke gets worse. I have not had the enricher off yet so plate (if I am imagining this correctly) is not backwards. I made some progress with the idle adjust. I got rid of the smoking on the left side and replaced it with smoking on the right side. Since I changed a couple variables at the same time I'm not 100% sure if that was the complete fix.

    I messed with the carb floats before I fired it up plus yesterday. I swaped the jets needles etc to see If I could put the blame on those parts. The swap did not seem to do anything by itself though. Tomorrow Im going to fiddle with the idle adjusting screws a bit. It was the first positive change I've had so I'm going to see what more will come from adjusting these.

    It seems like there was infact some starvation of gas as the bike just quit after several smoke-free minutes of running. This was welcome:1drinkThanks so far for the detailed advice. I use to spend a lot of time on thesamba.com and got great feedback and advice for my bus. I am happy to know there is such an active resource here!
    #14
  15. opposedcyljunkie

    opposedcyljunkie Heavyweight Boxer

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    I think you got it the other way around. Thes eare Bing CV carbs, right?
    #15
  16. bowerbird

    bowerbird BMW R65

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    They are bing 32mm CV carbs. Does out=lean? If not then I'm more confused.
    #16
  17. bpeckm

    bpeckm Grin!

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    Bing carbs use an idle passage with an idle jet and an air mixture screw. For good, basic information,

    read this article

    and it is well worth getting the Bing book, which is inexpensive and will tell you more about carburetion than you will ever want to know.....

    So YES, the air screw is turned OUT for more air at idle circuit. Generally, turn it out until it stumbles, then turn it back in somewhat. If you are turning it out more than a turn-and-a-half or so, you may need to clean the air passages. Be very careful with spray carb cleaners and soaking cleaners: you don't want to get that stuff on the throttle-plate o-rings, as they are a bear to replace.

    Anton has a good thread on rebuilding the carbs, as well


    If you find that you are still rich, away from idle, first thing to check is your float levels. Read his article for good detailed instructions.

    :wink:
    #17
  18. bowerbird

    bowerbird BMW R65

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    Thanks, I'll be reading these
    #18
  19. lkchris

    lkchris Albuquerque

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    Most likely way a Bing carb could be rich is overflowing float.
    #19
  20. bowerbird

    bowerbird BMW R65

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    One question I forgot to ask...How much fuel should I be looking to see in the float bowl say if I turn the petcock on , then off and take off the bowls?
    #20