Topic: Is this a known problem?

[Dirty Steve]

Doesnt prove it is clogged.
You are assuming you know what pressure it takes to force the float valves down.

Crack open a drain screw....let ALL the bowl fuel drain out.....then, turn on your tank fuel supply.
If more fuel flows out the drain screw, your fuel supply system works and is not clogged.
Close off the drain screw, and fuel should stop when the floats raise....and NOT flow out the overflows.

Either way.  Carbs need to be detailed, followed by clear tube test to verify fuel height, and then a good vacuum sync (assuming all else is in order)

Sorry, when I said clogged I just meant the float valves appear to have a good seal and were preventing fuel in the line from draining into the carbs. I didn't mean I thought my fuel line was clogged.
I appreciate your time on this, by the way.
I am wondering now if you think connecting the tank to the carbs (outside of the bike) and turning on the tap is an effective way of testing the float valves.

[flybox1]

I am wondering now if you think connecting the tank to the carbs (outside of the bike) and turning on the tap is an effective way of testing the float valves.

Heck yeah! 
...but dont stop there.  do the clear tube test to be SURE what you adjusted the float valves to, is adequate.
Otherwise youre just hoping....

[Dirty Steve]

Is it same cylinder fouling all the time.. Not sure but running vibration might let a float leak that checks out otherwise.. Pretty sure that is what mine was doing..

Yeah, that's a good question. It is always #2, and I've been thinking that this pressure test doesn't take into account the vacuum coming from the engine and the vibration, as you say.
Here's the thing, I've used two different types of float valves. A set of 2.0s that came in an aftermarket rebuild kit with the bike. And a set of Kei Hein 2.5s that are presumably the original set (These are the ones I'm using now). The thing is, I've been at this for so long I am not 100% sure that I've got the correct needles matched up with their corresponding valves. I inspected them all and there are two different sets of needles with slightly different tapers at the tips. I made sure the ones I installed all had the same taper and that they seal (using the aforementioned pressure test). But as you said, I can't be sure that they're adequately sealing while the bike is running.
Now that I've reviewed my statement, though, I realize if this is true I should be having a problem with all my carbs, not just #2.

[Dirty Steve]

Thank you Flybox.
I will do the clear tube test as well.

[Dirty Steve]

If my float levels turn out to be fine and I buy a new set of Kei Hein float valves and the #2 plug still appears sooty black and evidence of gas pooling in the carb boots (airbox side) persists, can anyone see a problem with me adjusting the #2 float to 28mm (from 26mm) to lean it out a little?

[Dirty Steve]

'Cause I'll be out of ideas at that point...

[flybox1]

If my float levels turn out to be fine and I buy a new set of Kei Hein float valves  Why?  If the ones you have shut off fuel, they are fine  and the #2 plug still appears sooty black Idle plug chop and adjust your IMS to compensate for the richness and evidence of gas pooling in the carb boots (airbox side) persists It wont if your floats are set based on clear tube test results , can anyone see a problem with me adjusting the #2 float to 28mm (from 26mm) to lean it out a little?  You wont need to if these ^^^ are done and correct  

[mrbreeze]

The 26mm float height is an adjustment to get you in the ball park. The clear tube method will show you the actual level in the bowl. Same as when you bench synch your carbs. You are just setting the height of the slides to a certain measurement to get you in the ball park. The vacuum synch will show you that all cylinders are producing the same amount of vacuum. These two items are very important and not everybody is on board with that. You will constantly find people on here that think that if they measure float and slide height everything is golden.

[Dirty Steve]

Interesting! So you're saying getting the fuel levels right for each bowl may necessitate setting the floats at slightly different heights?

[Dirty Steve]

Thank you Flybox for your very thorough reply, and I will take your advice:)
I'm wondering, do you think there's anything to the idea that vibration, or possibly engine vacuum, could prevent the float valves from sealing even though they seal during a pressure test?

[mrbreeze]

Float valves either seal or they don't. No need to pressure them up. If they don't seal.....the gas will keep coming into the bowl so long as the petcock is open. The gas will keep filling the bowl until it reaches the overflow tube which will result in a puddle under the bike. If the tube or hose on the tube is plugged it will go into the intake and on into the cylinder and/or air filter. It's a good practice to turn the petcock off when not riding.

[mrbreeze]

Interesting! So you're saying getting the fuel levels right for each bowl may necessitate setting the floats at slightly different heights?

Yes. Same with synching the carbs. The slides will likely end up at slightly different heights. As long as each cylinder has the same (or as close as possible) vacuum reading ..the cylinders won't be fighting each other to run.

[Dirty Steve]

Damn! That helps tremendously. Thank you for chiming in!

[Dirty Steve]

Float valves either seal or they don't. No need to pressure them up. If they don't seal.....the gas will keep coming into the bowl so long as the petcock is open. The gas will keep filling the bowl until it reaches the overflow tube which will result in a puddle under the bike. If the tube or hose on the tube is plugged it will go into the intake and on into the cylinder and/or air filter. It's a good practice to turn the petcock off when not riding.

I've never had fuel go out the overflows (I've checked numerous times to make sure they and the tubes are clear), but I have had it flood the cylinders and go into the crankcase early on in the process (and now it seems to be pooling in the intake boot of #2) and my feeling is it's happening while running (I'm careful to turn off the petcock when not riding). Is it possible engine vibration is causing the #2 float valve not to seal properly while it's running (even though it seals when it's off)?

[mrbreeze]

I guess it's possible but I've never seen or heard of it. I would do a thorough investigation on #2 carb. If the float is working properly and the fuel level is where it should be, this shouldn't be happening.

[Dirty Steve]

I will. Thanks.