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Author Topic: Carb pours gas out of bowl pipe  (Read 618 times)

dewane

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Carb pours gas out of bowl pipe
« on: October 10, 2010, 05:11:39 PM »
Hi, I've changed the float bowl and needle of both carbs. On the left carb, the bowl fills up then pours gas out of the hole/vent tube thing on the bowl. I pull the bowl, move the float up and down, it regulates the gas normally. I tried moving up the tang on the float, that did nothing (in fact, it seems to be spring-loaded all the time now - the float needle has a little spring-loaded part in it).

It did it twice yesterday when I was on the road - replaced the parts about two months ago and haven't had a problem since then. Today, I shot the needle area with carb cleaner to clean the passage - no difference.

What am I missing here? seems so simple. I'm stumped.

Oh yeah it's a '83 R65. I notice the left pipe is very black so it's been running rich for a while (I dropped the carb needle (not float but the carb needle) two notches a couple of weeks ago, I went from 30 mpg to - 30 mpg).

Thanks.
« Last Edit: October 10, 2010, 05:13:02 PM by dewane »

Offline Bob_Roller

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Re: Carb pours gas out of bowl pipe
« Reply #1 on: October 10, 2010, 05:13:53 PM »
My guess is that when you re-install the float bowl, somehow you are binding up the float, therefore it doesn't move and the carb overflows .

Just a hint here, the float hinge pin only goes in one way, the serrations on the one end mate up to serrations in one of the casting 'legs' on the carb .
« Last Edit: October 10, 2010, 05:17:26 PM by Bob_Roller »
'81 R65
'82 R65 LS
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!

Offline Barry

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Re: Carb pours gas out of bowl pipe
« Reply #2 on: October 11, 2010, 02:36:55 AM »
I had a carb overflow when this tiny spring clip was not fitted correctly.

This is one way of fitting it which works for me but it's not necessarily the correct way. As long as it isn't causing the float to bind  it should work OK. You could remove it to see if this is the cause of the problem.
« Last Edit: October 11, 2010, 02:38:07 AM by bhodgson »
Barry Cheshire, England 79 R45

dewane

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Re: Carb pours gas out of bowl pipe
« Reply #3 on: October 12, 2010, 11:49:56 PM »
You are a mind reader, I yanked out that wire thing. It didn't help, but it's like a "belt and suspenders" thing, as somebody else here wrote.

I finally fixed it - it still poured gas even after several checks with the old float, old needle, and combinations thereof. I also checked which way the pin that holds in the float was oriented - to match it with the serrations in the carb holes.

However, the entire carb points slightly downwards, towards the cylinder. The float on the left raises from the cylinder side when the float bowl fills with gas, and the floats are not handed (left or right is the same, according to BMW).

I thought about it for a while and tilted the carb slightly, maybe 10 degrees (I rotated the top of the left carb away from the bike).

Seemed to work! I guess the tilt offset the downward slant. The other carb on the right is pretty level. Seems to run great.

I also used a soft rag to clean out the place where the needle goes into, and the float seemed to have a very, very tiny bend in the middle (maybe literally 1 degree), so I straightened that out. One of these things fixed it.
« Last Edit: October 12, 2010, 11:56:34 PM by dewane »