Was this happening before the clutch disc replacement ??
I did a generic search for R65 grabbing clutch, may want to check the cable adjustment, it was mentioned .
What grease did you use on the splines ??
By chance did you aply too much grease on the splines ??
Grease can be pushed off the splines then get thrown onto the clutch disc .

My 79 R65 is running like a champ now and I get it out and ride it around the north Georgia mountain roads both paved and gravel.   When I got the bike I replaced the clutch disk when I put in a new rear seal and lubed the splines.  I did not replace the clutch spring or the pressure plate.  The old spring and pressure plate looked ok.  But first  gear seems grabby to me.  First gear in the R65 is pretty high but that ratio is what it is.

The clutch cable and the  position of the arm seem right .  But tryin to carefully and smoothly slip the clutch seems difficult.  I have had two oil heads  before in which I just replaced the clutch discs and they both  had clutches as smooth as silk.  Should I replace the spring and pressure plate and see it that changes the clutch engagement or is that rough clutch just a characteristic of the design. 

Winter is coming and I have a heated shop and enjoy working on the bike as much as I like riding it.  But I do not want to try and fix something that cannot be fixed .   What do the old hands think?

The R65 is a good bike. A little different from the other airheads. Unique styling. Technology and design language are the same as the other models of its era but fewer of the parts are interchangeable compared to other models. It was never as popular as the other models. Being the smallest of the lineup left a stigma. But a 650 is a full-sized bike. The R65 has ample power for practical purposes but not enough for thrills unless you really wind it out. The engine is highly over-square, meaning that it CAN be revved higher and MUST be revved higher to access its 45-ish horsepower. Which I rarely bother with.

OK another SciFi review (ish). Starfleet Academy......

Episode 1 is mass of action that draws you in, with the perennial baddie identifed - to come back later. Other episodes range from soap, to actually quite good. Episode 8 is Proper Sci-fi and got my attention though. 9, and 10 TBW.

I can foresee the replies coming, but I posted anyway. Love? Hate? 

Update: My issues were caused by a failed, almost-new battery.

I spent a quality evening going over connections, cleaning things up, looking for shorts. Time well spent.

Eventually I thought to shoehorn in a known good battery off another bike, and sure enough, the charging system behaved as expected, sticking right around 12.2V at idle and consistently climbing to 13.9 off of idle.

I just got back from having the battery tested and it is confirmed bad.

Tiedie: I have my idle set to right around 1000rpm after it warms up (it is about 800rpm on startup). My gen light goes off as soon as the needle lifts above 1k. Sorry to hear about your wandering idle issues!

.

Great news for you ! Yes I'm digging into it and sorting it out I'll let you all know when it back together and running.