If the break is near the backing plate check to make sure that there are no cracks in the plate that would allow air leakage into the crankcase. Drill a hole in the broken standoff and mount the needle vavle body to the firewall or motor mount. I've done this on a couple of remote needle valve motors. One FX, with good results, you will have to lengthen the fuel line from the carb to the nv of course. Just don't go too far away from the carb and try to keep the nv on about the same level.