Author Topic: Fuel leaking from carburetor  (Read 359 times)

Offline Athame57

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Fuel leaking from carburetor
« on: February 09, 2020, 03:06:24 PM »
My nearside carburetor is leaking fuel. I've taken the carburetor bank off and so far removed the bowl but couldn't see anything obvious...what to do?
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Offline Nurse Julie

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Re: Fuel leaking from carburetor
« Reply #1 on: February 09, 2020, 03:10:04 PM »
Where is it leaking from George, the overflow pipe, the float bowl O ring or elsewhere?.
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Offline Athame57

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Re: Fuel leaking from carburetor
« Reply #2 on: February 09, 2020, 03:19:40 PM »
I rode home switching the fuel tap off at every stop because it was draining from the overflow pipe. That pipe from the very bottom of the carb.
« Last Edit: February 09, 2020, 03:21:22 PM by Athame57 »
I brake for animals!
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Offline Nurse Julie

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Re: Fuel leaking from carburetor
« Reply #3 on: February 09, 2020, 03:21:56 PM »
I rode home switching the fuel tap off at every stop because it was draining from the overflow pipe.
Stuck float valve or debris in the valve seat would be my first port of call.
Im a Nurse, trust me, this won't hurt.....much !!!

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Offline Athame57

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Re: Fuel leaking from carburetor
« Reply #4 on: February 09, 2020, 03:49:42 PM »
Thanks Julie!  :D
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Offline Bryanj

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Re: Fuel leaking from carburetor
« Reply #5 on: February 09, 2020, 04:32:00 PM »
The yanks swear that the standpipes inside the bowl crack and let fuel through but i only ever seen 1

Offline Lobo

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Re: Fuel leaking from carburetor
« Reply #6 on: February 09, 2020, 09:41:00 PM »
I ride my 400F only occasionally and often (at fuel on) get a carb overflowing. (probably coz I run the float bowls dry after every outing). Anyways, when & if it happens, just a medium tap on the offending bowl with a screwdriver handle and all fixed. Possibly the float pins need polishing, but given my sporadic use and effort to remove the carbs it’s one I can live with; if I used the bike daily it’d be unacceptable.

Offline mike the bike

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Re: Fuel leaking from carburetor
« Reply #7 on: February 09, 2020, 09:45:16 PM »
I once lost a full tank of juice onto the tarmac because of a sticking float.
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Offline Athame57

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Re: Fuel leaking from carburetor
« Reply #8 on: February 09, 2020, 10:39:36 PM »
I once lost a full tank of juice onto the tarmac because of a sticking float.
Did it melt the tarmac at all like I've done on the communal veranda? ;D
I brake for animals!
1978 CB400F2

Offline mike the bike

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Re: Fuel leaking from carburetor
« Reply #9 on: February 10, 2020, 05:53:37 PM »
No.  It all ran down hill and evaporated.   There was a large ball of ice on the carbs from the evaporation.
If at first you don't succeed, skydiving is not for you.

Offline jeremypeachey

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Re: Fuel leaking from carburetor
« Reply #10 on: February 12, 2020, 04:39:28 PM »
When cleaning jets and float valve port I used a small kit of tiny brushes and fine steel wires bought off eBay. Worked for me. Wires are slightly abrasive and need to be used sparingly.
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Offline Athame57

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Re: Fuel leaking from carburetor
« Reply #11 on: February 13, 2020, 04:18:20 PM »
Well, I've had time to continue, my carbs are externally clean and shiny. I've had the tops off, not much to see there, and the bowls off. I cleaned them out and the jets too. I ran into trouble trying to remove the floats, when I started slackening the screw that holds them in I saw that the floats advanced upwards and seemed to be pressing the carb, so I stopped there wondering if I might break something?
I brake for animals!
1978 CB400F2

Offline Nurse Julie

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Re: Fuel leaking from carburetor
« Reply #12 on: February 13, 2020, 04:38:55 PM »
The screw doesn't hold the floats in place George, that's the brass pin that does that. I think the screw you are referring to, holds the plate that holds the jet in place. Just pull the brass pin from the pivot point of the float tower, peg things and the floats will fall out.
« Last Edit: February 13, 2020, 04:41:23 PM by Nurse Julie »
Im a Nurse, trust me, this won't hurt.....much !!!

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Offline Deano400

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Re: Fuel leaking from carburetor
« Reply #13 on: February 13, 2020, 07:42:08 PM »
You can see the pin Julie is talking about on the right of the post. You can tap it out to release the float.

Offline Bryanj

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Re: Fuel leaking from carburetor
« Reply #14 on: February 13, 2020, 08:34:46 PM »
If you are going to tap do it very carefully and lightly as the alloy(ish) posts are easy to break and impossible to repair.
Personally i prefer to grip the exposed part with parralel jaw pliers then twist and pull, carefully clean any burs and varnish before refitting.

 

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