Carburators with seat 2.0 ?

[4pots1969]

I just saw that I had a set of carbs with seats with the 2.0 keihin mark and my other carbs have the seats with the 2.5 mark?  However I did not find a different reference has 16125-235-004 even on the carbs of K1?
Obviously the hole on 2.0 is 2 mm and the one on 2.5 is 2.5 mm.

Which basic model does the reference 235 initially correspond to?
Who would have information about these 2.0 seats?

[4pots1969]

I found the code 235 match pattern, this code corresponds to a CB175...
Why put seats with a reduced filling rate...  Is it according to the different fuel
of one country compared to another?
The jet slow come in several sizes with different references ...
Why is it not the same for the seats?  Did we have 2.0 seats in France in the 1970s?