12000kms or every 2 years. You need to get on that machine and ride. 6k a year just doesn't cut it.It's in the service manual, but nobody really knows why. Some USA owners actually have 24000 (15000 miles) specified in their owner's manual. Some have found valves out of adjustment by 24000 Kms; http://www.ninja650.com/phpbb/viewtopic.php?t=9260&highlight=valve+interval
I'll just check mine at 1000 Kms, then at every 12000 Kms/2 years, just for the hell of it...
That's good to know!This is an old thread, but you guys might be interested to know the mechanic at my Kawi dealer says, so far, the inspections they've done have indicated no nead for adjustment. This is a truly great little motor. Put really good synthetic oil in it and go, baby.