With a 1/2" & 9/16" open end hex wrench back off the jam nut on the clutch freeplay adjustment on the down tube.
Inspect the 3 drain plugs magnets as its another eye into what is happening in there. Also, inspect and replace if needed the drain plug o-rings.
At this time lube your clutch cable from here towards the trans and at the left bar lever towards the adjustment. Also lube the lever pivot point. Use a good cable lube.
Now with a 7/32" allen and a 11/16" hex wrench or go-thru ratchet loosen the clutch rod jam nut.
Now spin the rod in (clock wise) till it makes contact and then adjust back out the clutch rod a 1/2 - 1 turn (counter clock wise). Do this a few times noting the position of your allen wrench to ensure you get it right.
At this point your shop area should look something like this.
Lets continue...
Tighten the clutch rod jam nut to 100" lbs or about 9' lbs. Be sure to not rotate the 7/32" allen in the clutch rod. This will adversely effect the clutch adjustment you just completed.
Now go back to the clutch freeplay and adjust the lever freeplay to 1/16" - 1/8" freeplay at the lever. An old school trick is to make the lever hold a dime in the pinch point.
Once you completed that, check the clutch operation while watching thru the open derby cover.