Gas pouring from carbs.

[3Phase]

... could the cylinder 'hold' vaccum enough to keep the petcock open?

Swing and a miss!

Mmmmm nope! The diaphragms have tiny little vent holes in them so they won't stay open when the engine is turned off.

And now, back to your regularly scheduled thread!

.

[motoman]

Swing and a miss!

Mmmmm nope! The diaphragms have tiny little vent holes in them so they won't stay open when the engine is turned off.

And now, back to your regularly scheduled thread!

.

What's the count?......................

[3Phase]

What's the count?......................

3 and 2 with a runner on 3rd.

.

[Ken Talbot]

Swing and a miss!

Mmmmm nope! The diaphragms have tiny little vent holes in them so they won't stay open when the engine is turned off.

And now, back to your regularly scheduled thread!

.

Of course, those tiny vent hoses are prone to getting plugged with spooge. When plugged, the vacuum that is created when the engine is running, which pulls the petcock diaphragm over to allow fuel to flow, does not release when the engine is shut off, which allows the petcock to keep passing fuel.

When you are inside the petcock, ream that wee orifice wide open with a piece of wire so it will never plug again. That will solve the leaky petcock problem. Then all you have left to do is fix the leaking float valve(s) problem.

[3Phase]

Of course, those tiny vent hoses are prone to getting plugged with spooge. When plugged, the vacuum that is created when the engine is running, which pulls the petcock diaphragm over to allow fuel to flow, does not release when the engine is shut off, which allows the petcock to keep passing fuel.

When you are inside the petcock, ream that wee orifice wide open with a piece of wire so it will never plug again. That will solve the leaky petcock problem. Then all you have left to do is fix the leaking float valve(s) problem.

<Vin Scully> "And it's a line drive past first base!" </VinScully>


Or the P.O. could have put it together wrong so the hole can't vent, then got rid of the bike because it kept leaking fuel all over the place.

I agree: Fix the leaking floats first and then worry about the fuel taps.

.

[Wolf]

Thanks for all the advise
There was no problems before i started the rebuild, so i can only blame myself
I agree, i'll focus on the carbs first, since thats where the leak is the biggest problem. I'll inspect and clean them thoroughly when i get the bike back.
The vent holes in the petcocks, where are they exactly? I think i saw a guide in here once, but now i cant find it.

[GLoweVA]

Thanks for all the advise
There was no problems before i started the rebuild, so i can only blame myself
I agree, i'll focus on the carbs first, since thats where the leak is the biggest problem. I'll inspect and clean them thoroughly when i get the bike back.
The vent holes in the petcocks, where are they exactly? I think i saw a guide in here once, but now i cant find it.

Here's a thread showing the internals:
http://www.xs11.com/forum/showthread...tcock+diaphram

Look down to post #13, 5th, 6th & 7th picture.

[Wolf]

Oh yeah, pretty easy to see those vent holes now. Thanks.
Just got the bike back from upholstering, and not a drop of gas coming out of the filters now so i'll probably leave it be for now. I'm thinking a little piece of something got flushed out or at least moved, so the needles can close properly now. If everything goes well, this will do for the season. A quick oil'n'filter change and i'm out of here
Probably give those old petcocks an overhaul though, since the "new" ones have the gas lines pointing downwards and not in, which makes the pod filters get in the way.

[jetmechmarty]

Thanks for all the advise
I think i saw a guide in here once, but now i cant find it.

Wolf,

After you get the carburetors sorted. The link below will get you through fixing the petcocks.

Rebuilding Yamaha Vacuum Operated Fuel Valves (Petcocks.)

[Wolf]

Thats exactly the guide i was thinking of
Not from in here then