Over the past several months my '91 K100RS with 60,000 miles on it has developed an increasingly loud knocking noise at idle. Louder than the usual clutch rattle, this also doesn't go away when I pull in the clutch lever... We also have an engine oil leak coming from the tranny to engine joint and out the weep hole. Paging through Clymer they mention a Service Bulletin from 1988 that had something to do with bad springs in the output shaft. Can somebody enlighten me? I clearly need the put a new main seal in so dropping the oil pan to work on the shaft appears to be just a few more bolts away. I had been planning to get a lift this winter anyway I guess this just moves it up on the priority list.