I just received some rubber tipped float needles for my 1/27/17 Bing carburetor from the Bing agency. They are about 1mm longer than the ball/spring originals, but otherwise fit perfectly. A little readjustment of the float level solved the problem. The part number is 47-916S and cost $9.34USD.
I have used those rubber tip needles from bing. It worked ok for a couple months, then one day my bike would not start. It was not flowing fuel. I blew in the tank to pressurize it and the needle popped open. While riding every so often it would run lean after a long strait. I think it was sticking.I put the old metal tip back in and its been fine.I have a friend who expirenced the same type problem. He could not get the jetting sorted out because of errattic fuel flow.Yours may work fine but I felt you should know.
I just rebuilt a bing carb with all new parts and put in the rubber tipped float needle. I had the same sticking problem as Dave.
Hmmm...now you tell us. These weren't cheap either. I think I'll try and wrap a piece of safety wire loosely around the needle-nubbins and the float tab, so as the fuel level lowers, the dropping float will pull the needle open, as these needles were designed for. (note: needle-nubbins: the thingy that touches the float tab) :~D