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Thread: Right side carb flooding

  1. #1
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    Right side carb flooding

    Came out of coffee shop other day to find puddle of fuel under right carb--always turn off petcocks, but was only going to be a few mins. On ride home, fuel was pouring out of carb out of any and all openings, rather exciting ride! Ive blown out carb twice and looking at float needle seat is good. Replaced float and float needle with new. Adjusted tab so that float is just touching needle and cleaned out tank and fitted new in-line filter BUT IT still leaks!!! With the bike sitting on stand, if I pull the bowl and turn on fuel, it flows. Slowly move float up with finger and it will shut off, so I know it should be working, but when its together, it just pours fuel out.

    This just started out of blue. The only thing that is different on this carb compared to the left is that the piece of round metal that sits at the very top of the carb dome is loose. Any thoughts on resolving? Appreciate the help. Jim

  2. #2
    Registered User donbmw's Avatar
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    Here is what I found with my own problems like that. Fuel line leaking. Float leve to high, float sticking, float needle and seat problem and float bowl corroded and developed a pin hole leaking fuel.

    Don

  3. #3
    beemerfield
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    I found a pin hole leak in a float bowl also. Be sure the fuel line isn't leaking upstream from the carb.
    beemerfield

  4. #4
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    adjust float height as directed in one of the on-line tutorials (don't know the specific places; Ausherman's?).
    if it shuts off when float is raised, but floods when you let it go, the problem is right there. (unless you have a porous float bowl, but that's somewhat rare). also, the float bowl gasket can leak or get torn/misplaced, so check there as well.
    Ride Safe, Ride Lots

  5. #5
    #4869 DennisDarrow's Avatar
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    Quote Originally Posted by jimv View Post
    Came out of coffee shop other day to find puddle of fuel under right carb--always turn off petcocks, but was only going to be a few mins. On ride home, fuel was pouring out of carb out of any and all openings, rather exciting ride! Ive blown out carb twice and looking at float needle seat is good. Replaced float and float needle with new. Adjusted tab so that float is just touching needle and cleaned out tank and fitted new in-line filter BUT IT still leaks!!! With the bike sitting on stand, if I pull the bowl and turn on fuel, it flows. Slowly move float up with finger and it will shut off, so I know it should be working, but when its together, it just pours fuel out.

    [COLOR="black"]COLOR]



    The only thing that is different on this carb compared to the left is that the piece of round metal that sits at the very top of the carb dome is loose. Any thoughts on resolving? Appreciate the help. Jim
    Sounds like a float height setting to me........If it was a fuel line or debris in the needle valve/seat it would still be leaking when you raise the float bowl.....pretty common condition, for me, I set the fuel level in the bowl to 23mm sometimes 27mm. This is measuring on the inside of the circle there in the bottom of the bowl up to the height of the fuel...............Have the petcocks turned off, put the bowl in place by holding it, turn on the petcock for a few seconds, turn it off, remove the bowl, measure fuel level, adjust float height................continue until you get desired depth.....


    Do you mean the dime sized round piece is LOOSE there in the middle of the dome?.............That chamber has to be tight in order NOT to loose vacuum.........what to YOU does LOOSE mean???..........God bless........Dennis
    Last edited by DennisDarrow; 08-30-2012 at 05:42 PM.

  6. #6
    Jack Ethridge
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    Leaking Carb

    Try cleaning the neddle jet with a Q tip & Pipe cleaner with brasso. That solved that prolem for me.

  7. #7
    Jack Ethridge
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    Leaking Carb

    I should have said the neddle jet Seat.

  8. #8
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    "With the bike sitting on stand, if I pull the bowl and turn on fuel, it flows. Slowly move float up with finger and it will shut off, so I know it should be working, but when its together, it just pours fuel out."
    =================================================

    This quite often means that when you put the bowel back on the float is rubbing on the side of the bowel or on the overflow tube - sometimes overflow tube is bent by forcing bowel back on
    Maybe part of cork gasket is being forced inward when bowel pushed up and interfering with float

    "Adjusted tab so that float is just touching needle"
    ==========================================

    This doesn't sound right - if overflowing is the problem one would adjust the tab so that the float
    causes the needle to be pushed up earlier and with more force thus reducing the level of the fluid standing in the bowel

    Are you absolutely sure fuel is coming out of carb and not from hose just above carb - the black fabric covered hoses that look so nice and original are crap and the fuel wicks along the fabric making it hard sometimes to see where it is really comming from

  9. #9
    Monza Blue 1974 R90/6
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    Quote Originally Posted by jimv View Post
    The only thing that is different on this carb compared to the left is that the piece of round metal that sits at the very top of the carb dome is loose. Any thoughts on resolving? Appreciate the help. Jim
    One tip to fix this I heard about is to use the green loctite. Green is the one you use on fasteners that are already installed. I haven't had this problem on my bike, so haven't personally tested it.

    Regards,

    Barron

  10. #10
    Benchwrenching PGlaves's Avatar
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    What kind of float? OEM two foam blobs? These can be damaged with ethanol that dissolves the varnish off the surface. Then the float absorbs fuel. The heavy float sinks in the gas in the bowl, failing to shut things off.
    Paul Glaves - "Big Bend", Texas U.S.A
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  11. #11
    Registered User rapz's Avatar
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    When I got my '79 it had nasty rust inside the tank and had your problem every few miles or so. I just popped the bottom of the float chamber off, let the gas run to clean out the jets, and back on the road with no problems, at least for a while. I got tired of that so I bought two small fuel line filters and have had no problems since. I have a video of them somewhere on my blog (address below).
    Website: www.airheadmoto.com
    IBA No. 58411
    Current Bike 1979 BMW 100RT; 2013 BMW R1200RT 90th Anniversary Edition; 2008 Harley Davidson Ultra Classic 105th Anniversary Edition

  12. #12
    Registered User rapz's Avatar
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    Here's a photo of the fuel line filters I use.
    Attached Images Attached Images
    Website: www.airheadmoto.com
    IBA No. 58411
    Current Bike 1979 BMW 100RT; 2013 BMW R1200RT 90th Anniversary Edition; 2008 Harley Davidson Ultra Classic 105th Anniversary Edition

  13. #13
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    Quote Originally Posted by rapz View Post
    Here's a photo of the fuel line filters I use.
    This filter looks like a Briggs & Stratton 691035 (I've seen it referenced as a part number of 491629) shown below. It is one of the two types that I use on my airheads. It’s a 40-micon filter with single-barbed connection bosses that fit the fuel lines perfectly. It is also compact at approx. 38mm/1.5” body length. They are available off the shelf in the lawn mower supplies section at Lowes and Home Depot.



    The other filter I use, shown below, is the ITW Fastex-CVA “Visu Filter” 8419 (FF701C). It is a nominal 55-micron filter with double-barbed connection bosses that also fit the fuel lines perfectly. It is very compact at approx. 25mm/1” body length. This filter has a clear PET housing. Many powersports stores carry them.

    Last edited by R100RT_Mark; 09-07-2012 at 12:28 AM.
    Mark

    Current - 1974 TR5T : 1993 R100R : 1994 R100RT ~ Past - 11# 1970s BSA/Triumph Singles & Twins : 2# 1970s CZ 125s : 1# 1985 BMW R65 : 1# 1976 Moby X7

  14. #14
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    right side carb flooding

    I am ready to throw in the towel!!! I have drained the tank twice. I have replaced the petcock stainers--the ones in the tank, put new inline fuel filters on along with the petcock stainers, so each line has two. Pulled the petcock apart and cleaned. Replaced the float needles and floats with new bmw parts. I have removed the carb and cleaned it three different times and every opening that I could find is clean. The diaphrams are new in both and the bowl gaskets are new and sealing no crimps. The fuel lines have been replaced with new Goodyear rubber. Pulled bowl off and set it on workbench. Filled it with fuel to the top to see if bowl or overflow tube is issue, its not.

    Each time it would overflow, I would pull the bowl and find small bits in the bottom of bowl. I DIDNT check the "T" since fuel was running thru it just fine, BUT when I did, I found a black looking pea pod stuck in the tube that is horizontal, not the vertical section. After cleaning this out and cutting the pod open, I found a fly so my source of the bits and pieces even after all of this was this maggot flaking apart! I did have the lines off for a week or so in the spring and never blocked the T's, guess that was the source of the pieces making it past the filters since this was downstream I now have this section that runs under air filter bypassed to try and isolate issue.

    However, I still have the right side overflowing. So I swaped floats and needles left to right and sure enough, the right overflowed within a mile ride!!!! I have measured the tab on each float and they are the same. I know, sounds like something is still not allowing the needle to seat, but I can find it................

    BTW, I used a socket the size of crimp on the dome top I was able to seal with a few hits and that is longer loose.

  15. #15
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    Sounds like the contamination from the maggot is still in the system. I would replace all the fuel lines and tee's. A piece of masking or duct tape will prevent crud in the fuel lines if disconnected in the future. Good luck!
    Last edited by Stan_R80/7; 09-07-2012 at 10:10 PM. Reason: added comment
    Stan

    AH# 13238

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