38 mm Carb on a 125? How? Which bike?

[kingriz1]

I have a mikuni 38mm flatside carb. I also have two bikes.

91 rm 125. FMF and rad valve
93 yz 125 bone stock.

1st question- what is the benefit of the larger carb? Bottom? Top? All over?

2nd which bike would benefit the most. (the two listed above)

3rd-what jetting would I start with.

Thanks a Bunch!

Sincerely,

Riz