rebuilt BS34 problem after high RPM

[jonny]

I just rebuilt my set of BS34 carbs, but am having a problem. After I ride in higher gears, 4th and 5th at about 3500 - 4000 rpm when I come to a stop and attempt to start from 1st the engine almost dies when I give it throttle. If I let it idle for a bit (less than a minute) it seems to ride like normal again. Spark plugs look like a copper color, but not glossy. I can't tell if this is a fuel rich or lean problem as I've made adjustments both ways. Right now my mixture screws are 3 1/8 turn out and for the BS34 the needles only have one setting so I haven't adjusted those in any way. The needle jets are seated almost flush with the inner lip where the main jet screws into it in the bowls.

 

[5twins]

Check your float levels. The BS34s are very picky about that.

 

[jonny]

Float levels are good I checked and double checked. Turns out my gas cap wasn't venting properly, some type of debris was clogging the hole in the gasket, so the bowls weren't getting refilled quick enough. I just went for a spin and she was running nice.