To much fuel

[lazzytrkr]

I have a 1980 850. It is blowing gas out of #1 & 2 carbs until it starts to overflow airbox. HELP? Carbs have been rebuilt, all though I'm starting to question how well he did them. Also have new petcock.

[gearhead13]

Who did them? The only way of knowing it is done right is to do it yourself.

[lazzytrkr]

Didn't know how. So paid to have them done. What's causing this. Have been told floats? Exhaust valves?

[Guest]

Rust in the fuel tank?
Was it the same guy that did the carbs that told you it was the exhaust valves?

[tkent02]

Who did them? The only way of knowing it is done right is to do it yourself.

What he said, or send them to someone like Chef.

[Guest]

Petcock gave up the ghost and fuel is coming down through the vacuum line and flooding everything out

Edit: Missed the part about the new petcock, still would double check. Send them to Chef

[tom203]

Before blaming carbs,be sure to check/understand petcock operation- don't leave it on "PR"

[lazzytrkr]

pet cock

Ok on the petcock. Wow! Never thought of that. Well, I have new petcock, just not installed & bike running yet. Thanks

[Tempted]

A good thing for us to know is if it is doing this with the bike turned on or off or both. It it only does it when the bike is running then its probably the floats. If it only does it when the bike is off its probably the petcock. If it does it all the time it could be either.

Carbs are very simple. The float pushes up when the bowl is full, shutting off the fuel to that carb until the float lowers. If your floats are in good shape and operating correctly then it shouldn't matter whether the petcock is left on prime or "on" or reserve. They will stop the fuel from over filling the bowls. The petcock vacuum hose gets its reference from carb #2, if its allowing fuel to leak through the diaphragm then you will get fuel puddling whether the bike is running or not.