The owner wants a fully usable clutch, so here's the mods it takes to make one from a sandcast/early K0/1 version.
First task: identify WHICH early clutch assembly it is: there were several types before the late K2 standardized them.
-The 1st type had a Lifting Ring for the outer plate or two (depending on which way it was installed), that was a free-riding part of the assembly.
-The 2nd type had a thicker rear steel plate with a steel wire that wrapped around the inner hub and poked into a hole to seat it: the wire(s) held the steel plates in place by retaining their teeth into the hub. Most had 2 of these wires, but the 2nd steel plate was normal thickness. There were only 6 cork plates in this version, and it only came in Old Factory bikes. It much resembled the CB160's clutch setup.
- The 3rd type, which came after the sandcast and late in the K0 series, had 6 cork plates and 7 steel plates, with a steel plate riding against the outer spring retainer plate in place of using that top plate as the last one. These, IIRC, came from the New Factory.
This sandcast has the 1st type, with no steel wire nor thicker backplate. Since there are no holes in the hub to retain any steel wires, it came this way originally. It was the first clutch design, the original IN/OUT box version. The twisted shifter arm splines tend to support that idea: it was a bugger to shift in city riding.
To improve this, the hub needs to be modified to have oil holes to feed the oil from the (now enlarged like later bikes) mainshaft oil feed hole. The steps are:
1. Make Oil Passages in the inner hub to feed oil from the mainshaft's port: the original Oil Passages are so small that barely a dribble of the tiny amount that got there from the tiny mainshaft hole even made it to the outer (top) clutch plate.
2. Make Oil Feed Holes directly into the clutch plates (like all the later 750s have).
3. Add the Oil Sipes to the inner side of the Clutch Hub to help gather the oil from the new ports and feed it into the plates.
All these things happen by centrifugal force when the engine is sunning.
Here's the original Clutch Parts Diagrams from the old Parts Manuals (1970s era). Notice the odd steel plate with the wire(s) for the clutches that had them, and the Lifter Ring in the pictures: in the Parts Listing shown here (this one was for K2 after March 1972) the numbers for those parts are simply not listed, which indicated they were discontinued - but might show up in an engine if it was recycled in Production from an earlier day into a later bike!
