I've been searching deep in my archives (it is 27 years ago i sold my last cb750) and i found these gear ratio's for theF2:
1st gear 2,500:1
2 1,708:1
3 1,333:1
4 1,133:1
5 0,969:1
I can't find the ratio's for the earlier models, but i seem to remember the 4th gear was 34:31, which should give 1,096:1, and the primary drive for the F models was shorter too, but i can't tell the numbers anymore,you could look at hondachopper.com