Carb leaking

[IFixAudio]

Hi,
Sorry if this is the wrong place for this. I'm trying to navigate this site.
I saw a post years ago on carb leak repair but the lack of float seat seals didn't apply to the 79.
Is anybody aware of a fix for the 79 Special? I keep getting over flow into my airbox with new needles and seats.

Thanks

Jim

[DiverRay]

1. Make SURE the vent tube, top "T" fitting, is not blocked!
2. Check that the floats do not "hang up" on the bowl gasket
3. verify that all 4 floats are set to EXACTLY the same height
4. Bench test the carbs, use a "C" clamp to secure to a 2X6 or something to keep them level, turn upside down, and put fuel into one pair at a time. Thee should be NO FUEL flowing out of the carbs. Once they hold that way, install bowls, flip over and add fuel again, one pair at a time. I keep a remote tank with shutoff and have it about 2' above the carbs. Let it set for 5 minutes per side, looking for any leaks.

[IFixAudio]

Hi Ray,
Thanks for the advice. I'll try that. This method should reveal something!
Would you have any idea why the bike "coughs"?
I mean at idle it runs ok but there is a stop every once in a while. I have new boots and I don't believe its a vac leak.
Best way of explaining it would be that is sounds like:
"da da da da da tah da da tah da da da da da tah da da da tah......"

Sorry, best way I could explain it...

Thanks again

Jim

[donebysunday]

Hi Ray,
Thanks for the advice. I'll try that. This method should reveal something!
Would you have any idea why the bike "coughs"?
I mean at idle it runs ok but there is a stop every once in a while. I have new boots and I don't believe its a vac leak.
Best way of explaining it would be that is sounds like:
"da da da da da tah da da tah da da da da da tah da da da tah......"

Sorry, best way I could explain it...

Thanks again

Jim

Jim, how long did it sit before you or a previous mechanic got it up and running ?
How long have you had it ?
Sitting longer than a month ethanol breaks down, soaks up moisture from the air, moisture will not fire.
I'm thinking some crap in the fuel is passing through (LUCKILY) the carbs. This would also explain the cough, when some of this crap goes through a carb and will not fire, cough.
Though if it's real regular in it's da da da da da tah it may be ign. ?

Ray is spot on !
One thought though is it leaking all the time or only when you park on the side stand ?
Could be float bowl fuel level is set nice and high and then leaning over the fuel flows to the lower carbs (leaning on the side stand) and flows past the float bowl gasket/s, if the engine is for the most part running fine new gaskets are in order to stop the overflow/leak.
You have checked the petcocks and Ts between the carbs ?
Just use a couple fingers and wipe the bottom of the petcocks, look for wet fingers with fuel on them, same on the Ts and the bottom of the float bowls.
Your tracking down the leak from the beginning, the tank, petcocks, carbs Ts last the float bowls gaskets.

[donebysunday]

Hi Ray,
Thanks for the advice. I'll try that. This method should reveal something!
Would you have any idea why the bike "coughs"?
I mean at idle it runs ok but there is a stop every once in a while. I have new boots and I don't believe its a vac leak.
Best way of explaining it would be that is sounds like:
"da da da da da tah da da tah da da da da da tah da da da tah......"

Sorry, best way I could explain it...

Thanks again

Jim

Jim, how long did it sit before you or a previous mechanic got it up and running ?
How long have you had it ?
Sitting longer than a month ethanol breaks down, soaks up moisture from the air, moisture will not fire.
I'm thinking some crap in the fuel is passing through (LUCKILY) the carbs. This would also explain the cough, when some of this crap goes through a carb and will not fire, cough.
Though if it's real regular in it's da da da da da tah it may be ign. ?

Ray is spot on !
One thought though is it leaking all the time or only when you park on the side stand ?
Could be float bowl fuel level is set nice and high and then leaning over the fuel flows to the lower carbs (leaning on the side stand) and flows past the float bowl gasket/s, if the engine is for the most part running fine new gaskets are in order to stop the overflow/leak.
You have checked the petcocks and Ts between the carbs ?
Just use a couple fingers and wipe the bottom of the petcocks, look for wet fingers with fuel on them, same on the Ts and the bottom of the float bowls.
Your tracking down the leak from the beginning, the tank, petcocks, carbs Ts last the float bowls gaskets.
Re-reading your first post about this I take it it was not leaking before the new needles and seats.

[motoman]

.....unless the new needle/seats were K&L and not Genuine Mikuni.
JAT, as I've fought with K&L float needles before.

[XJkid]

1.2. Check that the floats do not "hang up" on the bowl gasket
.

This was the cause of my XJ leaking fuel into and out of the airbox. I pulled the suspected float bowl and trimmed the gasket with a razor flush with the inner surface of the bowl, problem gone. I learned of this fix here from these boys.

[mschor]

Could be the seat needs a little polishing if the other fixes don't stop the leak?

[motoman]

.......a q-tip and metal polish works for that.

[skids]

.......a q-tip and metal polish works for that.

I have done that. Make sure that no cotton fibers are left behind...