Even better fit a dellorto carb, if you can find one.
You can check the diaphragm in a few seconds, take air filter off, pull back slide, let go, if it snaps back instantly the diaphragm is holed/split, if it takes 2 secs or so and returns gently it's ok.
The VV is not a performance carb, but is a very good all round carb, giving few problems.
I've retrofitted some astras that have had weber carb conversions to the trouble some Pierburg 2E3, which when set up right gives better power and better mpg than the weber
carb, so don't just jump at a weber, thinking all is rosy.
tabetha