Not sure where I picked up this information - and not sure it applies to all bikes - so I invite your corrections and additions. But the info, and any exceptions, need to be widely known.
YOU CAN upshift or downshift a TRAVELLING motorcycle with a broken clutch cable. (I understand that some racers, using maximum RPM, prefer not to use the clutch for upshifts.) The important thing to know, for most of us, is that firm pressure on the gear lever with a roll-off on the throttle will allow you to make a gear change in either direction. It will be a bit jerky but not damaging to your transmission.
This happened to me a number of years ago not too far from home. I was on a backroad, got down to first gear, and had almost a mile to contemplate what I was going to do when I encountered the stop sign on the busy two lane hiway I wanted to turn left on.
I eased up slowly feathering both clutch and rear brake. Though traffic from the right was solid, I did find a gap in the right lane and headed away from home, hugging the shoulder in low gear. When I got a break in traffic in both directions, I made a U-turn across the road. After that, I knew I had to run three stop signs to get to and up my driveway, and I did just that.
My feeling at the time (and still is) that if I had ever been forced to come to a complete stop, that bike wasn't going home under it's own power. (This was a 87K75.) Anyone push- started any bikes on level ground with no clutch?
Or is there some way I could have revved it up in neutral, pounded the lever into first, and gotten underway?
Broken clutch cables are not that unusual. And there are some great minds here. Fire away.