Cam chain rattle question

[Fazerjon]

Hi folks, just bought a (fairly cheap) 2000 Fazer 600 with 19,000 miles on. It sounds like the cam chain has a rattle. The oil level is correct and I just took the tensioner out and there is lots of clicks left on it so am I right in thinking the chain is not worn? I put the housing back on and torqued it up then put the ball bearing, double spring and the other ball bearing in then the cap and torqued. Carbs back on and the noise is still there. Any suggestions, I can’t imagine the cam chain is nackered after 19,000 miles. Are there any tricks or tips to get the tensioner to come out a bit more? I tried the rear wheel in gear backwards but this didn’t help either. I’m stumped at the mo. Noise eventually goes after a few miles once fully warmed up.  :'(