Foaming fuel pouring into airbox

Hello all! I just bought a 85 xj700 Maxim, hasn't been started in years. I first drained All the fuel from the gas tank and replaced it with new fuel, charged the battery and started her up. When I did 15 seconds in, foaming fuel just blows straight through the airbox. Thinking it might be a stuck float needle, cleaned every part inside the carb. After reinstall, bike fired right up revs normal, bit still blows fuel through the airbox. Any ideas why this is happening?

 

Have you checked the oil? You may have a lot of fuel in the oil resulting in an overfilled oil pan causing the blow back into to air box. That might be the cause of the foaming.

 

Is it coming from the engine vent tube into the Airbox, or from blowing back thru the carburetors?

 

It's coming out from there

 

So, your crankcase is waaaay full. Bet it smells pretty gassy, too, right? See what tabaka said. If it’s gassy, you have carb and likely petcock issues to address.

If it’s NOT gassy, and NOT overfilled, then you’re getting extreme pressure inside the crankcase..... bad rings? Bad valve stem seals?

if it’s NOT GASSY but too full, you gotta drain some out.