I had a close call today 60 miles from home, almost had to call a tow truck. Am I right in thinking this was caused by a stuck needle?

The background is that only two weeks ago I set the float levels and cleaned the carbs, synced cards. Starts with choke until warm up, idles at 1200 just the way I would expect, and even idles as low as 500 if I lower the idle screw, so I think the pilot and idle circuit is good. Runs faster and stronger than it ever has.

1. Ran it hard for two hours on back roads, and it was great. Breathing right and pulling hard.
2. Pulled over for lunch and afterwards, when pulling the bike up off the sidestand I hear a very loud air suction sound coming from the tank. Never heard that before and it's odd because I had just filled up, so where is the vacuum problem?. Starts right up though.
3. Ride for a bit and it stalls at a stop light. Started up again and it feels lumpy, as if its running rich. Losing a bit of power, but its intermittent. I ran through the powerband a few times and once it ran as expected and idled just fine, twice is hesitated around 3000rpms and then took off fast. Seems to stall only after running high RPMS, followed by a quick stop.
4. Stalled again so I pull over and smell fuel. Looking down I see a lot of fuel dripping out of the overflow hose that connects to airbox. This means fuel is overflowing and the float levels are too high. It's dripping fast, like a 2 drips a every second.
5. Pull over and it stalls, and will not start. I remove the damn fairings and check the plugs, they are dry and gray so not flooded or fouled.
6. Knowing the bowls are overflowing, I open the float bowl drain screws and drain them both. Knowing the fuel level is too high, I close the pilot air/fuel mixture screws down to lean it out some. I then crank it over with choke off and throttle wide open and it starts.
7. Running pretty good but feels lean but I dont want to be stranded again so I hit the highway and ride straight home. Just in case its still overflowing, I ride with 6000-8000 RPM's the whole way, hoping to keep the fuel moving.
8. Get home and put it on side stand. The fuel has stopped leaking from the airbox hose.

If the float is down (aka open) the needle can sort of jam in the open position.
Usually a few sharp taps on it will get it moving in that case. As far as possible tap the bowls upward to keep the thing from leaking out the gasket.
Cool.
Buddha.

I wonder why it's sticking. I looked at the rubber tips and they have no wear. Maybe hole it goes into wore, but how would a rubber tip wear metal?  These are ten years old though, so maybe I should just replace the whole assembly on both sides? OEM is only sold as a set

Quote from: Darkstar on April 15, 2018, 04:35:57 AM
hole it goes into wore,

OMG ... you're so bad.
No, its likely a coincidence. Take it off and set the height right and make sure it wont open far enough and play with it and make sure it wont jam.
I've got several years of use from that type of float neelde/seat. You could replace em, but likely the shiny new Chinese ones will crap out a lot faster then OEM ones.
Cool.
Buddha.

Quote from: The Buddha on April 15, 2018, 09:04:10 AM

Quote from: Darkstar on April 15, 2018, 04:35:57 AM
hole it goes into wore,

OMG ... you're so bad.
No, its likely a coincidence. Take it off and set the height right and make sure it wont open far enough and play with it and make sure it wont jam.
I've got several years of use from that type of float neelde/seat. You could replace em, but likely the shiny new Chinese ones will crap out a lot faster then OEM ones.
Cool.
Buddha.

Im confused. I set the heights just two weeks ago, checked the valve needle action. Do you know what changed to make this happen?

The float needles leak more often AROUND the push in seat where the O ring is. Especially if they have been out or worse been cleaned with carb cleaner, acetone or other VOC's. Common problem with this particular model of carb ( drz400sm's do it as well).
You need ned O rings for the outside of the seat. DON"T clean them with carb cleaner. If you must clean them Metho ill works and ensure they dry completely. The longer chain alcohols can be problematic as well.

Quote from: gregjet on April 15, 2018, 01:39:54 PM
You need new O rings for the outside of the seat

OK, I'll check them out. Also, in another forum I found the article below that says, "...metals that have been shown to degrade over time in the presence of high-level alcohol blends include brass..."  I found that in another forum where folks said that some needle jet heads seat on metal, and when the brass corrodes you can see it with a loupe, it looks pitted. They had good luck polishing them with compound and dremel.

http://www.ethanolproducer.com/articles/3033/properly-handling-ethanol-throughout-the-supply-chain

I think this will be the fix. Will be doing it Saturday:
https://www.youtube.com/watch?v=zlez_hdoWYk

Quote from: gregjet on April 15, 2018, 01:39:54 PM
The float needles leak more often AROUND the push in seat where the O ring is

This is far worse than a simple o-ring leak. I just replaced all the o-rings in these carbs, including the inlet, and it didn't help. There was a bit of white crud, but not enough to flood this bike the way it is. After start up, fuel leaks heavily from both the airbox drain hose and the top carb breather hose that runs between the carbs. I think I can eliminate the floats and needles because it occurs on both sides. Today, I also polished the inside of the valve needle holders, sides of the valve needles, and cleaned the jets. The action on the valves needles and needle plungers is very smooth, I submerged both floats in gas and they're not leaking, and the float bowl height is set right. I also checked that the rubber needle heads seals are tight by blowing into the fuel inlet hose. I checked everything with a loupe.

Here's the weird thing: when I initially set the float height and check with clear tube, they're right on, a few millimeters below the float gasket line. I did this after the standard 3-4 seconds of petcock prime turned on, then turning it to ON position to check. However, after I start the bike and it floods, I check with tubes, the fuel line is about very high, like 3" above the gasket line. This occurred three times in a row, and each time I opened the carbs up to check the floats, and carefully put everything back together.

I dont think this is a vacuum problem because it only leaks when the bike is running, it doesn't leak when petcock is in ON position and it's not running. Im stumped.

Petcock on and bike not running = no fuel flow out of the frame petcock.
Try it without the bike running in Pri. Then it will flow.
Cool.
Buddha.

Quote from: The Buddha on April 22, 2018, 06:19:42 AM
Petcock on and bike not running = no fuel flow out of the frame petcock.
Try it without the bike running in Pri. Then it will flow.
Cool.
Buddha.

Got it. Good advice, thanks. I tested with both tubes tied up and on prime and its good now. I also found a good chunk of white crud in the o-ring that sits between the inlet and the brass needle valve holder. Must have missed that when I tore it down over the winter. I think thats what started all of this, because it was running very well on a long ride and then just started flooding. Pretty sure that white chunk had lodged the needle open and thats why the fuel kept pouring. Then when I went to reset after cleaning, I hadnt let the bowls fill because I turned it to ON, so there was not way to measure the float levels that way!