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Right side carb flooding

jimv

New member
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
 
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
 
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.
 
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.

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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
 
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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.
 
"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."
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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
 
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
 
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.
 
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).
 
Here's a photo of the fuel line filters I use.
 

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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.

BriggsStratton691035240.jpg


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.

VisuFilter8419240.jpg
 
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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:banghead 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................:cry

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.
 
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!
 
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shut off gas
put a container under right side carb
remove float bowel
turn on gas and let some run into container
gently raise float till it shuts off - repeat this a few times to absolutely prove if the float needle will shut off the flow or not

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if this will not reliably shut off the flow then look for something like a hair or strand of something
hanging down through the tube and fixture the needle should be plugging when up (fly leg maybe)

use new hose from each side petcock to respective carb with no crossover till you figure this out
at least by doing this when on a road test you can shut off the overflowing side for a while and still keep going - some miles of this on and off just might clean things out
 
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.

Tell us you didn't hit it with a hammer! :scratch You might still have a leak...check it with some brake cleaner once running...see if the engine changes tune when you hit it with the spray. You might try, instead, using some silicone selant, clear, finely placed around the edges to create a good seal.
 
Flooding Carb

Check the needle valve, even it has the smallest amount of wear its time to go. Check it under a magnifying glass.
 
right side carb flooding

Its was a small hammer and very light taps!! I had the dome in my hand and gently hit the end of the socket to peen it back over. Once it was no longer loose, I did use clear sealant to finish it off.

The needle valves a brand new. This last cleaning has not resulted in any leaks--have left the petcock on and started it several different times letting it run 3-4 mins, shutting it off and then sitting. This would usely bring the flooding and it has not happened. SO, hoping to ride later today and then maybe out to Sandusky Ohio tomorrow, Sunday to try and catch the guys doing the cannonball 2012--I live about 80 miles east of there. Thanks again everyone for the help.
 
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