Weber/Dellorto carbs

[richard64 0]

I was replacing the air filters today on my car and above the left air intake trumpet on the Dellorto carbs there is a large hole  1.5cm. Does anyone know its purpose? It doesn't seem to be part of the main air path.

Thanks 

[calvinhorse 870]

On the air filter back plate? 
 

 

if so it’s for an air temp sensor usually 

[richard64 0]

Thanks, I have foam air filter s with no back plate (not sure if that is an issue) and the hole is exposed just above the air filter. The is no air temp sensor, Is it ok for the hole to be exposed or should it be blanked off?

[Thijs_Rallye 87 4 Cars]

I think those holes are the float chamber vents.