I have found more on Ebay, so it seems not a problem if I want a pair. In such case I might settle for a different design..
If anyone has just one laying around (like in the photo), let me know. The throttle side I think is 24 mm inside diameter
1982 Kawasaki KZ1300 A4
1981 Kawasaki KZ1300 A3
assembling engine, chassis & electrical from 79 - 89 parts