Gas from Airbox drain hose - volume 627

[NYNJ8]

...read plenty of threads on this topic.  My question is a straight forward one: Is a small amount of gas coming from that drain hose normal?  It is there for a reason, so I assume that is the case but just want to be sure.  Bike has not been used or left in prime position, always "on.". Got about an ounce or less drip slowly out after leaving bike on sidestand overnight - which I never do, always on center stand.

My initial hypothesis is that a small amount has been accumulating in the airbox and didn't have a chance to drain until I left it on the sidestand.  Either way, just want to find out before I start trouble shooting.  Going to order some spare carb components for a complete disassembly this winter but I want to ride for another few weeks before I do.

Background:
Bike had about 1-1/2 qt of gasoline in the crankcase when I picked it up a month ago.  Previous owner mentioned fuel leaking from that hose periodically.  I replaced air filter, changed the oil, and cleaned the float bowls and jets.  Probably will clean the drain hose this afternoon just to make sure it wasn't old gas stuck in the line. 

[The Buddha]

If its gasoline - you have a bad float seal or a badly adjusted float level.
If its a mix of gas, combustion by products and oil - you have blow by.

Cool.
Buddha.

[NYNJ8]

Thanks Buddha.  Don't know what a blow by is though.  Given the number of issues I read about trouble float needle seats, that would be my first inspection point.  The needles themselves were good when I checked a few weeks ago.  Will check float seats and float level...

If I drain the float bowls and let it sit without starting.  The bowls should remain empty correct?  If anything drains out again after letting it sit then I assume I have narrowed the problem down to a float seat?

[Big Rich]

If the bowls fill up after being drained, you have a faulty petcock (since you said it isn't left on prime). Now if you leave it on prime and it overflows, than you're looking at an issue with the floats.

Are you 100% certain it is gasoline? If you still have a stock intake setup, the crankcase vent will push steam into the airbox which condenses and goes out that same tube.

[NYNJ8]

Makes sense about the petcock vs float bowls. 

The fluid leak is gasoline though I cannot say with absolute certainty that it is only gasoline.  But I would guest that it is 90% or more gasoline based on the consistency and odor.

After the initial leak last night, nothing else has leaked out.  Seems like there was some gas in the system after the crab that made its way into the airbox.  I would think that if the petcock was faulty then the leak would be continuous.

IDK.  I'll go for a ride tomorrow and keep an eye on it. 

[NYNJ8]

Just tried draining the float bowl and an awful lot of gas is coming out.  Don't recall this much fuel coming in last time I drained it.  Gonna shut off the tank petcock and drain completely.  Sounds like a stuck float or bad seat.  Good timing because I was getting bored with the bike running so well....

[NYNJ8]

So I began draining the bowls and both bowls would not drain completely.  I shut off the tank petcock and both drained completely and normally.  Turned the tank petcock back on and both bowls began filling.  Frame petcock has been in "on" and never on prime.  So it seems my frame petcock is bad correct?

Also, since there was some gas coming out of the airbox drain (about a half once came out overnight) does that also mean that the seat(s) are bad as well?  Seems that their entire purpose for being is to shut off fuel regardless of what the petcock is doing, so I would assume so.  But is there any other way for fuel to exit the bowls other than the float needle?  How can I identify which seat needs to be replaced?

[Big Rich]

Have you checked the float level recently? Just curious.

You can take the airbox off and leave the bike sit overnight - any gas coming out of the carbs will appear under that particular carb (I do recommend putting something under the carbs to contain any spills). There is a possibility that it isn't the seats too. Could be a sinking or sticky float, bad float needle (dirty or worn), etc.

[NYNJ8]

Haven't checked the float heights but I'll be doing that tonight.  Gonna be close to 50 degrees tomorrow and I'm riding!

Petcock must have some issue too though because the bowls are filling without vacuum in the on position.  Trying to learn more about how the petcock works but it sounds like the diaphragm is failing?

P.S. I may just start calling my petcock a peacock because auto-correct is starting to piss me off!

[NYNJ8]

Upon disassembly I see that gas is entering the airbox from the cylinder head breather which attaches to the top of the airbox.  Can anyone explain this to me?  How and why?

Still may need to replace the petcock as the bowls continue to fill in the "on" position with the ignition off.  Or rather I'll probably just install a cutoff valve between the petcock and carbs. 

[floatingLomas]

I had a bad petcock - breached diaphragm - and it was causing fuel to leak from the tank into the (left side) carb through the vacuum line.  That fuel ended up in the oil, in the airbox, and also caused the left cylinder to not fire.

We removed (and lost ) the vacuum line, capped the petcock and carb ports, and it solved everything - and I rode it like that (using On as off and Prime as on) for like a month and a half (ok, well, four times in a month and a half ) before I finally swapped in the replacement.

As for oil coming in the breather, I would guesstimate that since gas is lighter than oil, when you fire it up, any gas sitting up top might be getting chucked about before it mixes in, and some of that would end up out the breather.  Are you sure it's coming from the breather and not the left carb?

[NYNJ8]

Yep, sure.  I pulled the filter and looked in the air box.  I could see a streak from where the gas was coming from.  Def running down from the breather.  The breather hose itself had a couple of drops of gasoline on it.  Damn peacock.  I'm gonna shut the tank peacock off temporarily and ride it until I get a shut off valve.  Still don't understand why the float seats don't do their job and shut off the fuel.  Bowls just keep filling...

[NYNJ8]

Took everything apart, floats seemed to move freely, but I gave them a stern look just to let them know I mean business.  Took the petcock apart, thumbed the diaphragm a couple of times, unplugged and reinserted all the hoses, zipped it all up and the problem is gone.  No clue what the problem was but I assume its a matter of time before it returns.  In the meantime I bought myself some more riding time until old man winter sets in.  I'll tackle this problem then.

As an aside, I plan to order a spare crab assembly so that I can always have a clean one with fresh jets ready to plug in.  See some on eBay for $150.  I'll just add it to the $1100 I paid for the bike and I still have a steal.  Love this bike and all its quirky flaws...