I have a pair of 7U with serial numbers 12915 and higher.    The clutch adjustment looks to be a yoke with a rod (see picture) and that doesn't look like the manua at alll.   Do I pull off the yoke and turn it to adjust it?

Pictures attached:

 

Hi, SkyMpCo.
I have never been inside a U series D4 clutch compartment. How-wevver, if it is like the earlier 2T and 5T series, there is a locking clamp with a bolt in it just behind the clutch itself and ahead of the yoke. Those clutches were adjusted by loosening the clamp bolt and turning the pressure plate a little until good pressure was felt on the clutch lever, then re-tightening the clamp bolt.

I believe there is a specification for pounds of pull at the top of the lever but have no idea what it is.

Just my 0.02.

You will need a 3/4" socket with a universal to get at that nut. You may find it easier to go in through the bottom cover.

Deas is correct on the adjustment.