The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Julio A. on August 29, 2013, 05:58:00 PM
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I had my carbs redone. I had the fuel level adjusted and set so that the float would be sitting parallel to the bowl and fuel level would be at approx 22-24mm. The fuel needle is new and its mating surface should be clean as it could be. Fuel would not leak within a span of a few hours, but if left overnight, would weep from the overflow. Even with the petcock turned off.
Does this mean I have to set the level even lower?
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I have had a fuel bowl that develop a seap that I thought was a needle not seating. Had a small spot of corrosion make pin hole seepage.
Don
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Check your fuel tap and see if it's shutting the fuel off .
There's a rubber disc in the fuel tap and it can develop grooves that will allow fuel to seep or flow even in the off position .
Back to the carb, if it overflows, the float needle is not sealing completely .
You have the float set correctly by what you posted .
Are the floats new, or old ??
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It is possible that the tip of the needle is worn or not seeting correctly, even though it sounds like you've set the fuel level to a normal level. It might be that some debris from the tank or from the inside of the fuel line might have worked its way down to partially block the seat of the needle, or (I actually have this problem on one of the carbs on my R100/7) there is a worn spot on the needle that causes it to sometimes bind and not smoothly push up when the float level rises. Another possibility is the metal "bridge" between the float arms is slightly askew or binding on its hinge post. And, sometimes one just has to *CAREFULLY* bend up the tab on the bridge that pushes up on the float needle - BUT I'd do this only after determining it isn't any of the previous things, and ideally it should be done with the carb off the bike and WITHOUT putting pressure on the hinge pin (Easily bent/distorted and that creates more problems)..
Heck, I am starting to sound like the snowbum now - must be I AM getting older.... :P
Also, along with new or old floats - do you have the original style yellowish white ones that are tied to a single beam, or the independent (black floats inserted on their own vertical posts) kit?
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I had the same thing until I replaced the floats a few weeks ago. Easy to tell by putting one in a cup of gas. It should float significantly better than an ice cube would in water (mine didn't). If I recall, the new ones had maybe a 1/10 to a 1/4 of their volume sticking up out of the gas.
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Is it possible there is a leak where the overflow tube is pressed into the float bowl.
You could remove the bowl, fill it with fuel and leave overnight to see if it stays dry underneath. Even if no leak is observed it would at least eliminate the bowl as the culprit.
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The fuel needle is new and its mating surface should be clean as it could be.
New part trying to mate with an old part. I'd consider replacing the needle seat.
Attach a length of fuel line to the petcock with the other end in a glass jar. Close petcock and check the jar after 24 hours+/-.
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Did Monte's petcock staright to the jar suggestion and found that the tap does leak. Although my karcoma is less than 3 years old and I just rebuilt it last week. New o-rings and that rubber disc with 5 holes. Funny thing though, it was leaking from the handle when I first installed it. That leak eventually disappeared then this happened. I'm tearing it down first thing tomorrow.
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If you don't find any problems with the fuel tap, when you take it apart, lubricate all of the rubber parts with a light grease or oil, don't assemble it dry .
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Found what's wrong with the tap.
Thanks for the help guys! :)
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi107.photobucket.com%2Falbums%2Fm292%2Fblaze_sniper%2F026b25620eca472cd8d614eb8484a3fb.jpg&hash=480e9146f646b80ed0b59cd60d1a8d983cf5706c)
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That will cause the problem, like I said, put some sort on lubricant on the rubber parts before assembly .
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Yup! I put some silicon based grease there, it should do nicely.
Leak tested it again after 2 hours. No more leaks.
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I'll second the suggestion to inspect the float bowl overflow tube - they can corrode and develop pin hole leaks.
Another one that's fooled me, and quite possibly what's happening here is deterioration of the fuel line. What I've seen is it dries out at the bottom end where it attaches to the carb. It'll crack and start to seep before it fails completely. And because you can't see it on the back side of the carb, you only see the drips from the bottom of the float bowl and suspect an overflow situation.
So check the fuel line.
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Hey Guys, I just want to share this with you.
I was still having a slight leak every once so often with my carbs. I tried everything, isolated every possible sources of leaks for the past week trying to figure out why the gasoline level would always reach the overflows even with the float properly set.
Just a day ago, I found the problem. The carbs was not perfectly aligned(Horizontally) with respect to the engine. It was off at around 10 degrees. I this awfully misaligned angle interfered with how the bowls filled and its respective fuel level.
Aligning the carbs using the engine fins as reference seemed to solve the problem. I have been finally leak free for a whole day now.
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that's good info - thanks for the tip!
:)
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Hey Guys, I just want to share this with you...
I have been finally leak free for a whole day now.
Believe I've seen an advert for this product flash across the TV. Something to do with cars, or roofs, or... plumbing.