Yesterday when riding the bike i just got a rattle sound when accelerating from 2000 to 3500 revs. Sound comes from right side top of the engine. It is not a metal sound. My mean it is kinda of loosy chain or tensioner problem. Anyone did have any problems like this before?
Any experience shared or helpful info would be appreciated.

Camchain rattle is a known issue on ZX-14s, but normally it occurs at idle when cold upon startup. If you have a lot of miles (or klicks) on the clock and have not had access to top-grade lubricants, the tensioner runners could possibly be worn and in need of replacement. The automatic tensioner only has so much length before it's fully extended and can no longer push the runners snugly to the chain. You can check the chain tension by pulling the head cover and rotating the motor to different spots to see if there's excessive play.

Just an idea from left field. If it's a 2012 or 13, check the plastic panel under the front of the windscreen. Mine needed a little tweek of the 2 lower screws because it rattled about the same RPM as you said. Just a thought that's real easy to try.