Here is a table showing how rich/lean the low speed jets are for Weber Dco/Dcoe
This can be used as a guide when adjusting

		Ø inside	Ø Air (side)	Number of air in
Rich	F6	2.0mm	0.7mm	1
	F12	1.5mm	0.9mm	1
	F9	2.0mm	1.0mm	1
	F8	2.0mm	1.2mm	1
	F11	1.5mm	1.2mm	1
	F13	2.0mm	0.9mm	2
	F2	1.5mm	1.4mm	1
	F4	2.0mm	1.4mm	1
	F5	1.4mm	1.6mm	1
	F7	2.0mm	1.2mm	2
	F1	1.4mm	1.4mm	2
Lean	F3	1.4mm	1.6mm	2

If you have problems with the transition between low and high speed with, for example, the F8, we usually recommend trying the F9
The F9 has smaller air holes on the side compared to, for example, the F8
This makes the fuel mixture richer and then the transition between low and high speed is less noticeable
The larger the internal diameter, the greater the "fuel reserve" there is


Do you want to learn more about carburetors??

Then we have a very good Weber manual (English text) Art no: 95000-054

For Dellorto choose this (English text) Art no: CB101