Good, thanks for the clarification. Spaying more cleaner into the carburetors and chasing it with compressed air isn't going to work better the second, third or fourth time around. You've done all of the steps that typically leave guys right where you are with a bike that's still not running like it should. The only real step left is to take them fully apart. The carbs need unracked which means separate them individually and take everything out, soak them in carb cleaner or get an $80 ultrasonic cleaner and do it right. The YZF600R is a fantastic all-around bike. You'll be so happy if you just take the time instead of spending the same time to do the same things over again. You can get the carburetors close enough to know if it's going to run by syncing the carburetors with them off the bike. Go on YouTube and look up "bench sync carbs". Do this once you have taken the carburetors apart and soaked them individually with all of the parts removed. Just do it you will be glad.