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leaky carbs

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schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
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leaky carbs

Post by schrader7032 »

I don't think they're that notorious... First, are you turning your petcock off when the bike's not in use? You should but if you do and the carbs leak, you need to rebuild or replace the petcock. Second, have you checked your floats? Do they float or contain gasoline? They do develop hairline cracks which allow gas in and then they sink thus not shutting off the flow of gas. Third, the older carbs had seating problems with the float needle. I've heard people lapping the end of the needle with some grinding paste to help it seal better.

Another thing you can do is after a ride and a block or so from your house, turn the petcock off and let the bike run on what is in the float bowl. This will help prevent the gas from expanding and overflowing when you shut down and the heat from the engines get to the carbs.

Look into those things and see what works.

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

mutater22
Posts: 2
Joined: Wed May 28, 2008 12:52 pm

leaky carbs

Post by mutater22 »

thank you very much. That was very prompt.
I was thinking of the rebuild, I just didnt want to spend the money if
it was a notorious problem. Thank you again.

I will let you know how it went.

K.C. Ma.

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pierce7221
Posts: 38
Joined: Thu Dec 14, 2006 7:33 pm

leaky carbs

Post by pierce7221 »

seconding what kurt said. i just get in the habit of running the engine a bit after turning the petcock off. otherwise they do leak, particularly if on the sidestand.

drax
Posts: 4
Joined: Wed Jan 21, 2009 3:47 pm

leaky carbs

Post by drax »

My Bings were leaking copius quantities of gas right onto the exhaust pipe producing a hissing noise! I totally dismantled and overhauled the carbs (new o-rings, diaphragms, jets and new floats). Now they don't leak nearly as much--only a couple drops when sitting for days. When my carbs were off the bike getting cleaned, I noticed my petcocks were barely leaking--maybe 1 drop per day. When I have the time, I will overhaul them too, and I suspect this should stop the leaking all together.

At any rate, my 75/7 ran soooooooo much better after the overhaul. I cleaned out a surprising amount of dirt around the jets. I followed the Haynes synch instructions with great results--much better pick up, better MPG and far less vibrating.
R-75/5 Toaster, R-75/7

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VBMWMO
Posts: 1322
Joined: Sun Aug 23, 2009 7:49 pm

leaky carbs

Post by VBMWMO »

help. i am a new owner to a 1962 bmw r/50 and was told that the leaky carbs were notorious.
there must be a way to fix this problem since gas is so expensive.
if anyone has an answer i would greatly appreciate it thank you.
i hope im in the right area for this question. first one of these forums i have joined.
Dedicated to the Preservation of Classic and Antique BMW Motorcycles.

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