I've been trying to figure out this problem for a little while now, I'd like some input.  My bike is leaking gas from the airbox drain line.

Is the only thing that can cause this improper float height?  I looked at the floats and needles and they looked good.  The float height seemed good.  I turned the carbs upside down and tried to blow into the gas inlet.  I couldn't so that means the floats are properly working no?

When I start up the bike though, it'll run then bog and cut out.  Engine gets flooded and gas eventually starts dripping from the airbox drain.

One thing to note: I do have an aftermarket petcock.  It has ON, OFF, and RES.  ON is like Prime, just a gravity connection to the carbs.  In order to use this I had to use a vacuum cap to plug up that small vacuum connection on the left carb. 
Could it cause the engine to flood at all?  I left the petcock in the ON position (similar to Prime on a stock bike) overnight and it did not leak.  That should rule out a faulty fuel switch.

So I'm curious to hear some opinions on what it might be.  I'm no carb expert, but unless that vacuum connection may be the cause, I would guess that it has to do with the floats.  But remember I did try that little test which (i would assume) means they are properly working.

Any ideas on what I should do?  I'll probably take some pics of the floats and maybe some people on here might see something that I'm not.

Here's an easy way to see if your float heights are set correctly:
http://www.bbburma.net/FloatHeight.htm

Quote from: VSG on July 08, 2008, 04:59:07 AM
I've been trying to figure out this problem for a little while now, I'd like some input.  My bike is leaking gas from the airbox drain line.

Is the only thing that can cause this improper float height?  I looked at the floats and needles and they looked good.  The float height seemed good.  I turned the carbs upside down and tried to blow into the gas inlet.  I couldn't so that means the floats are properly working no?

When I start up the bike though, it'll run then bog and cut out.  Engine gets flooded and gas eventually starts dripping from the airbox drain.

One thing to note: I do have an aftermarket petcock.  It has ON, OFF, and RES.  ON is like Prime, just a gravity connection to the carbs.  In order to use this I had to use a vacuum cap to plug up that small vacuum connection on the left carb. 
Could it cause the engine to flood at all?  I left the petcock in the ON position (similar to Prime on a stock bike) overnight and it did not leak.  That should rule out a faulty fuel switch.

So I'm curious to hear some opinions on what it might be.  I'm no carb expert, but unless that vacuum connection may be the cause, I would guess that it has to do with the floats.  But remember I did try that little test which (i would assume) means they are properly working.

Any ideas on what I should do?  I'll probably take some pics of the floats and maybe some people on here might see something that I'm not.

Sounds like your floats -dont-. Think about that one. If the float goes lower, more fuel is allowed, more flooding.

Dunk your floats in a pan and see if air bubbles out. I bet they're shot, or the o-ring at the neck of the floats is dead/MIA.

Keep us posted.

I did take a look at them already and the o-ring is in good shape.  I didn't think of actually checking if the floats float.  That could be a good explination since the heights looked good.  I'll have the carb out tonight and will look into that.

If the floats sink ... out of that carb it will leak like a river ... It will not just get into air box, it will clean come over on the top T and run like someone turned on the faucet.
Cool.
Buddha.

quick update:

I started it up without the airbox so that I see if it was leaking out both carbs or just one.  Started it up and it ran great... for a few minutes.  Then, gas started pouring out of the inlets of the carbs.  I'm taking fire hose style.  It sprayed out enough to hit the battery!     Well that was enough to confirm that it was coming from both carbs.

When I get time I'm going to test out the floats to see if they're still functional.  Could it be there may be a tiny hole in the floats and it starts out OK, but then gets enough gas in it to sink?

Inlets ? what inlet, where you put the petcock hose in ?
Or the top T fitting - If that, you have a float sticking open or sinking.
Your floats looked fine, though I cant say I test each for sinking or floating ... cos ... well I never had one sink.
BTW if you have a sinking float (wont it be called a sinker at that point) - I'd send you one for mailing $. Cos, like I have never sold a single one. May have tossed a few really a few months ago.
Cool.
Buddha.

By inlets I mean where the airbox connects to the carbs.  It that called the air horn?

K very very very unlikely that both floats sink. Besides the thing will leak from the top T fitting if floats are sinking ... unless my guess is, you have wrongly routed the hoses. The fuel line should go to the lower T fitting on the back of the carbs, not to the top T. Is that where you have it fitted.
Cool.
Buddha.

Yes, it is routed to the lower connection.

Well the floats and carbs are great!  That's the good news.

The bad news is that it's actually oil & gas leaking out and there is gas in the crankcase. 

Ideas of what would cause that?

You leave it in prime? if so, fuel can overpower the float needle and get into the chamber, then trickle into the crankcase.
I do it on purpose with motors that have sat, add in some penetrating oil and let it soak up in there a few days, or months in my nighthawk's case, then wonder how the crap got in the crankcase ... 
Anyway, the solution is ...
Drain it, put in new oil and make sure you dont put it in prime.
Oil and gas mix in crankcase can make a lot of pressure as it gets hot, then we will get pressurised crankcase and it can blow out various gaskets if the vents are not capable of taking it.
Gas is also not that good a lubricant.
You should not put it in prime, that is a crime and if you didn't put in prime, the petcock is bad.
Cool.
Buddha.

Is prime bad while the bike is running?  Or just if it's sitting?

Bad when sitting.
Cool.
Buddha.

Looks like that was the cause!  The petcock was either bad or in prime over the winter.

Drained out the oil/gas, cleaned the carbs, replaced the spark plugs and it seems to be running fine now.

Ok good. Atleast you didn't wonder like I did when there was gas and crap in the oil ... huh, where did that come from, cos the gas tank was not even on it for several months. Turns out I put gas and penetrating oil in the chamber to free it out, and I pushed the bike in gear without spark plugs to nicely get the cylinders cleaned. 
Anyway, that thing had a geyser out of its crankcase vent when it got warm. Crazy honda I thought 
Cool.
Buddha.

Had a similar problem with my sons TTR125.
Was running great all summer since I put in a new pilot and jet to help with
starting problems.
We go to put it in the garage and notice fuel coming out like crazy.
Go to turn off the petcock and that does not help.
We siphoned out the gas through the top and looked at the situation.
Float was obviously stuck or had something stock in there.
Took it all apart and did not see anything obvious.
Checked the float action and it was fine.
Took the hose off the petcock and it was leaking when in the off position.
Took and apart and did not see anything wrong.
Put it back together and it worked fine.
I guess the bike just needed attention.
What was strange was the volume of gas that was coming out.
Much more than I would have expected.

I had the same problem with the 96 500e I bought off CL last week.  I adjusted the float level 5 times, dunked the floats to see if they sank, dunked the carbs with the bowls removed etc etc etc.  then I found this post in the faq on this site:  http://gstwins.com/gsboard/index.php?topic=33930.0 . because this addressed my problem I knew I had to join this BB! 

I don't want to get off on the wrong foot by questioning a comment made by the legendary and helpful poster with 15000 contributions but I don't think that the petcock was your problem.  The float system should still work with the petcock on prime.  I can see how you might get a trickle flow rate past the closed needle valves,  if you let the bike sit it could become flooded etc.  but you described fuel coming out the main air jets (squirting right?).  by definition that meant that the needle valve wasn't closed at all.  You must have had a kinked vent hose or a blockage there that you somehow fixed even though you didn't realize it .  the link posted above describes the problem exactly and I'm thankful that I found it and this site.

I'm sorry if I have stepped out of line with this post as this is my first.  I will accept any sanction if deserved, I only wish to continue to learn from this site as I am having fun with my first bike in 10 years.  dave

I have seen several bikes that will push the float needle open if you park them on prime with full tank of gas. In theory it will close it in spite of being in prime - cos I have seen several bikes that will do that too. But Some combo of luck, aging parts, design of the fuel system, the bends in the hoses etc etc can play a hand.
I'd just not sit it with the petcock in prime.
Yea ... I ahve become legendary ... whoo hooo ...
Cool.
Buddha