They serve 2 purposes..
1. If fuel leaks, it drips clear of the exhaust manifold/pipes.
2. They help stop the fuel getting too hot in the fuel bowls due to heat radiated from the exhaust. It will run without them, but may be more prone to vapour lock in traffic.
Having said this, I just realised my Dellorto doesn't have or need one...
You can make one out of steel, aluminium or S/S. There must be an air gap between exhaust-heat shield- bowl.
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
