Two entries for today. I forgot to post the first one when it occurred last Fall.
1) The ignition switch on the K75s froze solid and wouldn't turn on. Luckily I was at home not stuck on the highway. It only went from Off to Park, and refused to go further round to ON. Looked online and the lock is NLA anywhere, and battered used ones are daft money on fleabay. What to do? I took it off the bike and gave it a 30 minute bath in the ultrasonic cleaner, filled with my usual mix of Yamaha carb cleaner solution, diluted 50/50 with distilled water. After that, the lock operates normally and turns to all 3 positions smoothly. I think the original factory grease had finally dried up and jammed it. I read all kinds of "how to" pieces on stripping it down to clean it and they looked daunting. Lots of springs and balls to lose! This way I just dunk the whole lock assembly in one go, have a cup of coffee, then dry it off. Treated it with water dispersant and then lock oil, and I was back on the road again.
2) Replaced the split fork gaiters that look like OEM from 1987. Yes, I got the Rancho ones recommended on here. While I had the fork legs off I replaced the fork oil as I had no idea how long it had been in there and if it had ever been changed. The 'unusual' handling problem was solved - I took out 250cc from the right leg and 150cc from the left. At least the PO had used decent fork oil and it was clean. Just not enough of it.