+- Austinsevenfriends (https://www.austinsevenfriends.co.uk/forum)
+-- Forum: Austin Seven Friends Forum (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=1)
+--- Forum: Forum chat... (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=14)
+--- Thread: SU carburettor swap (/showthread.php?tid=6146)
SU carburettor swap - andrew767767 - 21-05-2021
Hi what are the advantages of swapping out the zenith carburettor with an SU carburettor for a Ruby
RE: SU carburettor swop - Bob Culver - 22-05-2021
My expereince, which seems to match others on here, is that the 1 inch or 1 1/8 inch with dashpot but no spring in place of 26VA gives about the same increase in performance as the later head. Also very smooth with no flat spots. And polish nicely. The semi downdraught do not look vintage. Surprisingly, I found superior to a 26VA bored to 19mm but maybe did not experiment enough.
Changing needles for optimum results can be expensive and tedious although the cold start device enable testing for richness. However few now seek optimum economy.
If chance upon an Austin 10 carb with 19mm venturi could be worth a try.