OK. What did I miss.

[Suzuki Mad]

Stripped and cleaned the carbs. Fitted new 'O' rings, all seemed good.

Bench testing them before fitting on the bike, reserve bottle to main fuel feed for about 5 minutes and then fuel starts to drip from carb no 4. It appears to be coming out of the main appartture of the carb and just on No 4.

What did I miss?

All the bits inside look good, needles, float heights.

I'm baffled what to look at next.

I've stripped No 4 down again, checked the bits but cant see anything wrong.

[tom203]

I had a similar start up problem this year.....thought it was #4 carb leaking, but turned out it was the fuel feed tube from #3 to #4....apparently the o-rings dried out over the winter nap. I ignored it and they soon swelled up from the petrol and cured the issue.

[rphillips]

Dang, I can't believe ya'll mentioned this. For the past 3 or 4 yrs., the first time I start my Honda CB1100F in the spring, it drips fuel for appx hr. or so, then quits leaking. Good for the rest of the yr. Thought maybe a dried out "O" ring or seal, but didn't know for sure.

[Steve]

On a freshly-rebuilt set of carbs, it's possible that a needle valve might be sticking.

Tap the side of the carb with a hammer handle to jar it loose.

.

[Suzuki Mad]

Yep.

Done all new O rings, tapped the bowl with the handle end of my screwdriver and its still leaking. All I can guess is it's the needle valve has an issue that you can't see yet when it's in the carb its not functioning right.

It would probably work fine on the bike with the vacuum tap but I like them to be right so I am not putting a know problem into the bike to sit.

When I do carbs I do them singley so no parts can get swapped between carbs. What was in there was in the. No 4 did have all the rust in the bottom of the float bowl and was the dirtyest one of all.

[Suzuki Mad]

Stripped No 4 down this morning and found the fault. A very small film of black 'dust' on about 2mm of the float needle. Recleaned the brass needle seat and the needle jet, refitted and tested. No more leaking fuel.

Must have had remaining fine dirt in the fuel line that made its way in.