Motorcycle Repair: clutch issue, wont disengage, clutch lever, clutch cable

Question
I realize your more of a Honda guy, but vintage yamaha and honda should be close, mechanical wise...  i got a 72 yamaha LT2, the lil 100. it was sitting in a barn for about 20 years.. rolls smooth in neutral and goes into gear nicely, but once in gear and you use clutch-lever, it doesnt seem to disengage the clutch into that neutral state. pulled of cover and i can physicaly see the clutch cable/lever/nut-screw moving in and out when clutch lever is applied. does this sound like the plates are seised or rusted together? or maybe a cable-slack adjustment? it feels like a firm pull when i squeeze lever.

Answer
As you said, I'm more of a Honda guy but it sounds like the plates are just stuck together.  The lifter is working so it't not adjustment.  You'll probably have to take the clutch apart, oil up the plates and put it back together. I've often been able to get them to release by riding the bike around while holding the clutch in.  THe heat and torque of the engine will usually break them free.  Disassembly is a last resort.

Regards
Rich