Thanks. That's a useful photo and I will compare with mine today. I'm using the original 2 BA screws and fitting went fine apart from changing the throttle nipple. Silver soldered a new nipple. The cable adapter was too large in diameter to fit into my throttle grip. I imagine there have been many many types of throttle hand pieces out there over the years. If I can find a fix to the clearance issue I'll get some longer 2 BA cap screws. Allan keys are much easier to use on the carb tops.