The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: jgp1854 on September 03, 2012, 07:17:18 AM
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Had BING rebuild both carbs this past spring, installed BING's gas line. All has been well, now I'm getting a minor pooling on the throttle return spring bracket, that eventually drips onto the garage floor. I've replaced the bowl gasket to no avail. Re-checked the floats, and needle valve, both seem to be spot on. Did some close examination and noted where the gas line slips on over the "brass" nipple some dampness, which in theory run down the outer lip of the top portion of the carb and collect at the bracket???
I doubt if the leak was BING line, it is very, very snug, and requires some serious tugging to remove it. My question is: has anyone experienced the "brass" nipple leaking? It looks to be pressured fit.
What is the CW on OEM gas line vs. BING's line?
Thanks
Jim
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are you using clamps? i think if you're using the stock black cloth fuel line my bike came with clamps, i use the translucent blue fuel line now its 1/4" and i don't use clamps and never had any leaks.
is it on both carbs? or just the left carb?
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No clamps, using BING gas line, not the OEM fabric line. Only the RH carb.
Jim
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I had the same problem a few months ago... there was a dripping specially when I turned the engine off...
The diagphram had a small hole that caused it... could it be that?
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I doubt that it is the diaphragm, seeing BING just rebuilt both carbs installing new ones.
jim
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Jim,
Check the brass intake nipple's fit into the carb body. It's rare but occasionally the press fit can become loose and leak.
Only other thing I can think of besides the fuel line itself is; there's an overflow port opening just above the nipple at the inside corner of the BING plate. Just might be the float needle is hanging up with the bowl attached and the excess fuel is exiting the port opening. Have a close look at the needle attachment on the float tab and it's clip to make sure everything is free and not hanging up.
Float settings set correctly?
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... Float settings set correctly?
... and no bit of debris keeping the float needle from sealing all the way? Sometimes, a tiny bit of fuel line -downstream from a fuel filter- can come adrift and cause carb leaks. Even with the petcock turned off, there is still residual fuel in the lines just waiting for an opportunity to mess with you.
Been there. Still have the t-shirt. ;)
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How much fuel is supposed to be in the float bowl? I've heard 21 mm and 25 mm.
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Sorry. 32 mm Bing on '86 R65.
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Ron-Jim,
I've personally never measured the fuel height in the bowls. I have a static/crude way of setting the floats, some may agree and some may disagree but I've always had good luck with my procedure.
With the floats assembled and the bowl off - I take a spare clean fuel line and attach it to the fuel intake spigot. While lightly blowing through the fuel line I raise the float to be parallel with the carb body. If I hear the air from the fuel line stop at that point I'm good. If not I adjust the tab to the point where I hear the escaping air stop when the float is parallel. I will then follow-up with an individual carb wet test. With the bowl removed and the fuel lines from the tank attached, and a collection pan beneath the carb, turn the petcock on and raise the float parallel to the carb body. The fuel should stop flowing at that point. If not - I make an additional tab adjustment.
Obviously; take precautions with raw fuel in your workspace. Be sure to do one carb at a time and have a collection device for the fuel. No open flames - ensure adequate ventilation. I've always had very good luck with the air procedure and only once that I can remember having to make an additional adjustment on the tab after the air routine and setting.
Sometimes "shade-tree" works well.
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Thanks, Mike. Unfortunately, for right now "shade tree" is what I have.
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How much fuel is supposed to be in the float bowl?I've heard 21 mm and 25 mm.
I recall 22 - 24mm being the correct height. It's difficult to check accurately as you need to the whip the float bowl out of the way quickly otherwise the residual fuel in the fuel pipe adds to the contents. That can cause an error of several mm in the measured height. The exact level between 22 and 24mm is probably less important than both carbs being set at the same height so at least with new floats maybe the parallel shut off method is a better option or at if you measure the height in the bowls cross check that with the parallel method.
Truth is there is no way of being absolutely sure that the levels are correct when the bowl is on the carb short of a transparent float bowl or a sight tube. One of these days I'm going to do something along these lines.
I did read about one guy who removed the carb tops, diaphragms and main jet/needle jet assembly then poked a flexible tube into the float bowl from above. It's then possible to suck up the fuel and make a sighting U tube by bending the tube down below the bowl and back up again.
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Okay,
Here is what I've done, per BING:
Check float needle to ensure not hanging up, and fuel flow is shutting down, DONE.
Checked float levels, appears to be spot on.
Replaced BING BAI fuel line with BMW OEM braided line.
Switched float bowls with friend.
Replaced float bowl gasket x 2.
Tightened hose clamp twice, and rotated the screw mechanism on the hose clamp to the top, just in case!
Bottom line, fuel is still pooling at the bottom of the return spring bracket!
I know it isn't much, but it is the dam principle, they shouldn't leak. Prior to having them rebuilt by BING, (at the cost of $425.00 USD) the LEFT carb leaked, after having them rebuilt the RIGHT carb is leaking. I know of nothing else to check or do, so it appears I'm stuck with taking it off, and shipping it back KANSAS to see if BING can fix what they created.
If you have any other ideas/suggestions I'm all ears.
Borderline P..... O.. in Michigan
73516
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Could you post a picture of the fuel leakage leakage area, I'm just having a bit of difficulty envisioning your problem .
I've looked at my bikes and I'm lost on this one !!!
I thought of an unorthodox (and possibly hazardous) method to test the carb ff of the bike .
If you have a work bench vise, put the carb into it, with a piece of wood at each end to prevent the carb body coming into contact with the vise jaws .
Put a two foot length of fuel line on the carb inlet nipple, support the fuel line so it is straight up, to get a bit of pressure to it .
Put a small funnel into the fuel line, pour some fuel into the funnel and see if the leak becomes visible .
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I would do the check Bob said . If it leaks on the it should leak on the bench also.
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Bob,
I think I've attached (3) photos of the "pooling".
Jim
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Bob
Here are some views of the "pooling".
thanks
Jim
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From the pictures I don't see that as breather mist dripping from the inlet elbow. It's not the place oil would collect from that source. Sure the wind could blow it about but backwards not forwards.
I know you checked all these things but I suppose it could be the carb to head inlet rubber or a leaking bowl gasket. If it was pure fuel though you'd expect it to run clear once any external oil had been washed off.
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Barry makes an excellent observation.
Unless the camera is playing optical tricks with us, that drip collecting on the carb spring bracket looks to be a mix of oil and fuel.
The left-side carb is most often the source of excess oil leeching from the intake tube from air box. Just a thought here... Could the oil be due to an over-filled crankcase?
Thick silicone bowl gaskets are available for the Bings. If there is an inequity in the carb body-to-bowl mating surfaces, these thick gaskets are an easy fix.
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There's another thread about oil on the float bowl going on right now .
I'll have to agree that this looks more like oil from the crankcase breather, rather than a fuel leak .
What level do you keep your oil level at ?
I was guilty of always topping the oil level up and had a constant oil drip from the left carb .
I now keep it at about the half level and rarely get any oil dripping anymore .
I think I'd hold back on doing anything else with the carb , I'd remove the inlet tube on the left side, clean all the oil out and drop the engine oil level to about the half level and see if it helps any .
If you have the enthusiasm, remove the top cover on the engine and check the crankcase breather valve, it's just a reed valve type valve .
There's a small hole in the plate that the reed valve is bolted to, check to see if it is open, it allows oil to drip back into the engine after it's shut down .
It's hard to say, if a previous owner has been in there and forgot to put things back together correctly .
Honestly, I don't think you'll find anything wrong, this is just one of those 'quirks' the bike has .
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Barry,
I concur that it seems like it would be blown rearward, but what if it seeps and pools after shutting down? When the carbs were rebuilt, I installed new rubber inlets and plastic elbows on both sides. As noted, I've installed two new bowl gasket.
MM, BR
Typically, I fill the oil closer the to the top side, but short of the line. I will check today and see precisely where the level is. I concur that this looks like a mix of gas/oil. And I also noted that the connections of the plastic elbow and the carb, is adjacent to the "brass nipple", which I initially thought was the perpetrator, due to the dampness, and downward angel the carb is positioned to allow for the pooling on the throttle return bracket. But now the dialog on the breather inlet and oil level puts me on the trail of another suspect or two. I have a set of the rubber bowl gaskets, but will wait to see what I find with the inlet line and oil level.
I would also like to nominate the three of you for Honorary Doctorate Degrees in "AIRHEADOLGY". You guys rock!!
thanks
Jim
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A PhD in Airhead?
Well, Bengt Phorqs would say that pretty much describes me. :D
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MM,
Glad you saw the humor in it!
In checking the engine oil level, COLD, dipstick set in, not screwed in, the level was a freckle above half. Likely, a bit lower than what I filled it at during the last oil/filter change.
I've taken things apart since reading the responses. I found the air box general area to be dry. Removing the black rubber lines, I did detect small amounts of oil, I used a q/tip to dap up the residue in the crevices and general area where is was. Not sure if what I found was typical amount or an excess, just didn't seem like a lot? I cleaned the rubber fitted hoses and the clear plastic thingamabob that goes inside the plastic elbow and the rubber fitted tube affixes to. Not sure what else I can do?
I've attached some pics showing how it looked when I opened it up and how the oil appeared in the fitted rubber hoses for your perusal and feedback.
To the fine scholarly "Doctors", my heartfelt thanks.
Jim
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Bob,
You noted to remove the LEFT inlet lines? The issue is on the RIGHT side. Do I need to remove the left? I've removed the right and cleaned them.
Jim
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I don't think you really need to, from your pictures, it's looks normal .
One thing I would suggest, is to replace the gasket under the breather housing, or at least get some oil resistant sealer on it .
It will make a mess of things in that area .
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Bob
Pulled the cover off the breather housing and looked at the reed valve, it looks normal to me. I've included some pics, let me know if you things it looks like it is suppose to?
thanks
Jim
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Everything looks good there, all of the pieces are there and in good shape .
If the top cover you removed to gain access to the breather valve is difficult to get off and on, file the ends down a bit so it fits better .
On my '81 R65, you couldn't remove the cover if the engine has hot, it was that tight of a fit .