I've got a 2006 ZX6R 636 that overheats after about 10 minutes. The temperature sporadically increases and decreases, as in it will go from 92 to 103 to 91 to 94 to 115 to HI to 119 to 101 to 118 to HI to 119 to HI etc. So far I've replaced the temp sensor, thermostat + gasket, fresh coolant, and at one point we hardwired the rad fan to a switch so that we could control when it would come on, and we had it on from 80 degrees and up and it still overheated.
Took it to a shop, they had it for 5 weeks and couldn't figure out why it was overheating either. Apparently they were on the phone a lot with Kawasaki techs who also couldn't diagnose the problem.
The bikes only got 13 xxx kms on it, it's been very well maintained, and it hasn't even been ridden hard. It ran fine last year, winterized it as I always do, rode it for a week or two this year, and then parked it because it developed the overheating issue.
I'd love to get at least some riding in this year, so any help is greatly appreciated.