Float stuck?

[CableGuy]

Have been lurking here for a while now and I finally have a carb question.

1980 XS400 Special

Was driving home from work, about 2 miles into trip, and my Rpms started to shoot up. Throttle stuck wide open, 9000 Rpms. Got it shut down and pulled over safely. Can see that it's not the cable, and the shafts in the carbs rotate smoothly.

It's not home because a storm came through and I didn't want to mess with it in the rain. Don't worry it's in someone's garage. I can't stop wondering about it though. I am assuming it's a float problem. Has anyone else seen this before though?

Thanks in advance

 

[NewHavenMike]

Something got stuck....wide open

 

[Jeff0133]

Not floats has it would have flooded the air filter/airbox and would probably have bogged down rather than rev up.
Vacuum leak is a possibility...or maybe the slides stuck in the up position caused by carbon build-up from bacfiring through carbs or a damaged/ bent needle...idk

 

[CableGuy]

I will get it home tomorrow and find out.

 

[CableGuy]

Carbs looked really good so far. Didn't get much past taking them off. I did notice the vacuum line going to the petcock was full of gas.
I'm kinda mechanical but not that experienced, that doesn't seem right to me.
I could see that being a problem but it's only one cylinder. It's so fast and smooth to 9k rpm.

Learning as I go I guess.

 

[Jeff0133]

Well..there you go gas in the vacuum line is not normal