Topic: What did I do?? (Gas pouring out of airbox drain).

[F16Viper68]

I've been slowing returning a 1981 Honda CB650C to roadworthy condition.  For more information on my progress click on the link in my signature. 

Today's task was to swap out the carb insulators (vacuum leaks), bands, and throttle cables.  I've rebuilt the carbs (did not separate the rack) a month of two ago.  The bike's been running fine except for a vacuum leak stemming from badly cracked carb insulators. 



One thing I did do while I had the carb rack on the bench was to block the holes where the t-fittings went between the #1 and #2 carbs, holes on right side of #2 carb, left side of # carb, and between #3 and #4 carbs.   

I did this by cutting off the ends of plugs. 



I reassembled everything as I've done ten times, never took the carbs apart and the throttle action is smooth. 

But when I attached the temp gas tank I got a very rude surprise.  Gas was pouring out of the carbs!  I took a quick look and gas was dumping out of the airbox drain hole. 

I have not clue why the floats would all of a sudden decide to stick. 

Did plugging the t-fittings and holes on the #2 and #3 carbs do something?

Any help would be appreciated.  I'd remove the plugs just to see if it fixes the issue but dang it was a royal PITA to cut and install them. 

Dave...

[F16Viper68]

Okay, I see one thing I did wrong.  There's supposed to be a vacuum tube between the #2 and #3 carb.  I have the holes plugged.  I beginning to think I need to install a line betwen #2 and #3 and unplugged my handy work between #1/#2 and #3/#4.

Dave...

[F16Viper68]

Yep, don't plug them.  I was able to remove all of the plugs without removing the carb rack and my fuel overflow issue has been fixed.  I'll chaulk that up to a lesson learned and find a way to put the t-fittings back in when I tear it down for frame painting.

Dave...