New Carb Leak

[Bill2001]

New carb for my Wombat 94, bought from SH. The carb works well, but it has a small gas drip (maybe 1-2 drops per hour) from the "main jet banjo bolt" on the float bowl. I've replaced the aluminum washer with a new one, tried lapping a slight "manufacturing defect" from where the banjo bolt seals on the float bowl, but no luck--still seeps. Since it threads into pot metal I'm hesitant to overtighten it, and I'm not crazy about using sealant around jets. Is this a common problem? I'm inclined towards trying to use a softer aluminum washer or a fiber washer or buying a replacement float bowl. Ideas?

[viclioce]

Maybe try some Teflon tape around the bolt threads? ; D Victor

[Bill2001]

The threads on the main jet holder won't allow sealing tape.

[spudman]

Just thought I'd throw this out there...only as a possibility. The carb on my recent restoration project, a model 99 Road Toad...also had a small trickling leak on the bottom of the float bowl. When I rebuilt the carb, I put a new float bowl gasket in, along with a float bowl drain plug gasket. When I opened the petcocks this past weekend to start the bike for the first time, the trickle was back. Upon closer inspection, the gas was leaking from the overflow nipple. It didn't take me long to figure out that the float needle valve and seat were the only things I DIDN'T replace during the rebuild, and I know now that if that seat is pitted or corroded, the needle valve won't seal off the fuel flow into the bowl. I know your carb is a different configuration than mine, but look and see if you have that small black plastic overflow nipple on the bottom of your float bowl. If so, make sure the leak isn't originating there. Like any liquid, the gas will ultimately run to the lowest point...which might just be your banjo bolt when the bike is leaning on its side stand.

[Bullfrog]

I agree, the first step is identify with 100% certainty that the leak isn't somewhere above the banjo bolt. A good way to check is to do a thorough wipe down of the carb before going to bed, and then in the morning do some spot checks by wiping with white Kleenex starting at the top of the carb and working your way down. Where is the first place you find some residual oil left on the carb after the gasoline evaporated away? This is "new" oil - where did it come from?
Ed

[Bill2001]

Brand new fresh off the shelf carb with all new components. Seeping from the washer on the main jet carrier.

[Bullfrog]

OK then. Here are two suggestions:
1. Try a fiber washer. Fiber washers were commonly used at that location back in the day. (as were soft aluminum washers)
2. For an old fashioned fix/confirmation of leak location - look for a product called "SealAll" (hmmm, maybe it was "SealsAll"). Ennnnneywayeee, it is a type of liquid glue/cement for sealing fuel systems weeps which was created long ago. Try it at the banjo bolt washer. Note that it will "break away" anytime you need to remove the banjo bolt . . . and will need to be reapplied.
Ed