Diameter of carb mounting stub on forty models

[Stylo Seagull]

Hello All

Bit of a random question, but does anyone know, or could possibly measure the diameter of the carb mounting stub on the cylinder of a forty plus engine?

Would it be the same diamter for a forty featherweight? I'm guessing yes as they share the same villers carb?

I need to do a little job relating to this and won't get to measure for a few days.

If anyone could help me, i'd really appreciate it.

Thanks

[phil]

I just measured a couple and get .750" or 3/4" outside diameter. As far as I know there is no difference between a 40+ and a 40- block, I think this goes back as far as SJP/SJM. The difference in power is due to a different gearbox. The ones I measured where 60s and 70s motors?

Someone will correct me if I'm wrong on the blocks being the same.

[Stylo Seagull]

Thank you for doing that for me.... Very kind

The century plus I have comes in slightly bigger at 7/8"

[Rob Ripley]

And the carby from the C100 fits and runs without any changes .... 40 cc to 100 cc ! Why is that ?