AHL recommends 1.6 rim for 2.75/3.00 tyres.
Though fitting a 3.00 on 1.4 should not be a problem but not recommended.
Remember there are many GS riders using big a$$ 100/90 on stock 1.6 rim while recommnded minimum is probably 2.15 for that tyre.
Wanna know a fun thing, i am running 3.00 tyre with wide shiny 2.15 rim. Gangsta style