I just disassembled and cleaned my carb for the fist time because it would not idle without the choke on. It had sat for a long period of time and was gummed up and jets where clogged. Cleaned everything and reassembled it. After I got it back on the bike, turned the gas on, and checked for leaks I noticed a slow leak coming from the float bowl drain tube. I checked the bolt for damage and it seemed fine. Screwed it back in good and tight and still fuel slowly leaked out the tube. Is the bolt bad / damaged or did I not assemble something correctly? It started easily and idled / ran fine after warming up.

 

if its coming out the tube and the drain is screwed in all of he way then it is overflow. your float is eather sticking of not aligned properly and is not shutting off the fuel flow when it goes up. of something like it has a hole in it and it isn't floating it is probably stuck or a lil bent did you check the clearance when you had it off? your manuel should show you how. tap the bottom of the bowl with the back of a screw driver see if theat helps. when i first cleaned mine and put it on and started it it overfload so much it came floding out the air indake and bogged the engine down and shut off. i let is sit and the next day whent to pull it iff to see what i did wrong and said well lets try it again for teh hech of it before i take all of the plastics back off and it started ran great and no over flow it unstuck and fixed itself.

 

I had this same issue. You need to look in your service manual on how to adjust the float. If the float is bad you will need to replace it. I know what you are thinking because I thought the same thing. Yes there really is a pin hole in the tube coming up from the bottom of the carb bowl and it does bypass the bowl drain srcew and will allow gas the seep out if the float is set wrong. Look real close and you will see a pin hole about a 1/4" or so from the top of the tube.

 

Same issue here, flaot height was way off. On the 330 TB, it should be parallel to the float bowl mounting surface.