Why is my Kawasaki ZX-9R stalling?

Why is my ZX-9R stalling?
I own a late Kawasaki ZX-9R and it will only turn over and start when the bike is in neutral and the clutch disengaged. The moment I pull in the clutch lever it packs up. I’m not looking forward to stalling in traffic.
Nigel Easthope, MCN forums
 

Cut-out switches like the one fitted to your clutch lever are electrical switches that are pretty exposed and on the go all the time, so they do wear. BUT it could just as easily be dirty metal contacts or the wiring. Give the switch a spray of WD40 and/or contact cleaner to start with, clean those contacts and test the switch by bypassing it. They are about £18 new.