clutch problems causing vibration?

Ok,So I have a 1977 Kz1000 and I was starting to notice a vibration that I never felt before. I thought it could have been frame related,or even motor mount related. I checked all my motor mounts for proper torque and, inspected the frame for cracks and, all fasteners for for proper torque. After I tightened every thing and, inspected the frame for cracks I could not find any conclusive evidence that those were causing the vibration. So did a service on it and, I adjusted the clutch adjuster and, lubed and adjusted the clutch cable. It did good and, I rode it and, it felt better, I could still feel the vibration a bit but, I could not exactly place it, The motor sounds good and, there were not excessive metal shavings in the oil, so I was riding home from work today and, out of nowhere my clutch came out of adjustment and, was really slack. So slack that, I could not shift out of gear. I tightened the lever free play and, got the bike home. Now I read in a thread a couple of months ago about how vibration could be cause by a collapse in clutch springs. I had previously noticed on a slight difference in clutch actuation that made the lever feel almost spongy. Could a collapsed clutch spring cause this and, could it also be causing a vibration? I can really only feel it in my feet. the vibration in the handlebars is not really over noticeable. This is just buggin me, I fell like I may have it pinpointed but, Would kind of like advice from anyone who is willing to impart with there knowledge or personal experience. Thanks everyone.

A bad chain that has kinks in it will make a vibration when your riding. Have you checked the wheel bearings?

I actually just changes the wheel bearings about 2 months ago and, the chain is in pretty good shape, I lube it and, keep it adjusted but, it does have a slight tight spot. I will look into it. Thanks for the insight

i am thinking the clutch cable is slowly snapping a thread or two at a time... but not enough yet too "snap" all the way...anyhow...its the first thing i thought of..good luck..somthing small i bet when you find it....

....when i bought my 900 the guy "said" the clutch was new but I "might " ....need springs soon and that he "thought" the clutch "basket" was worn and hence "it slips a little sometimes,,,,but not too bad".... it slipped leaving a stop and shuddered too...i thought oh great a new clutch basket is a drag to do...but....
i bought a new set of performance friction plates and a set of heavy duty clutch springs and a new clutch cable and gasket..swapped everything but the metal plates at one time.......i have had no more shuddering or slipping under heavy take offs since and it will pop wheelies now.. and roll on hard in any gear......not saying that is your current problem at all just my clutch story...
also another experience ..clutch related
a broken/shattered friction plate will show up all of a sudden and make it seem that you've blown somthing up...cuase no shift,,no clutch..ect...but usualy happens while doing somthing hard on the clutch...i bought all that stuff of e-bay for like 100 and did the swap in an hour......good luck bro

the clutch cable is in good shape, I checked and, there are no frayed broken strands and, I lube it pretty frequently. I am probably going to go into the clutch to see if I can figure it out. I have not changed the plates since I bout the bike around years ago and, i do not think the previous owner took very good care of it. Thanks for your input.