Layshaft diameter

I've replaced the first gear bushing on my 74 850 and after pressing it into the gear it doesn't fit over the layshaft. I'll give it to a machinist at work to ream to size but I need to know what the shaft diameter is. It's too far inside the case to get calipers on it, does anybody know what the bush should be reamed to?

According to the Norton 850 "Stage One" Service Release N3/73.......

.........Technical Data:

"Layshaft diameter (kickstart end) .... .6855"/.6845"
"

Thanks LAB