KZ 250 Transmission related noise

I recently picked up a KZ 250 with an '81 model engine in it. Engine running fine no noise . Once I engage clutch and start driving there is a high pitched whine coming from the right side of the engine. It stops when I disengage the clutch so it appears to be transmission speed related. Just changed oil, adjusted chain etc. Any ideas?

Was the noise present before you adjusted your chain? Did you leave the specified amount of slack in the chain? Chain must have slack. Ed

Thanks for the reply. I put new chain and sprockets. Checked the slack and is about 1.5" to 2" at the loosest point. I will put on center stand and check again. Thanks