Which timing chain tensioner is fitted? The earlier wind up spring & screw type is somewhat failure prone. The later coil spring & ratchet mechanism is bullet proof unless mutilated by untrained hands.
This will not cause smoke.
No the smoke was a bit of a smokescreen, it doesn't really smoke. XTJoe actually meant that the engine has done some hours.
Alec and XTJoe and I had a look at this DRZ tonight. When removing the tappet cover we immediately saw that there is LOTS of slack on the timing chain, that probably made all the noise. Everything is intact up there, no debris lying around, no obvious wear. So we took off the tensioner. It is not a ratchet type, so I suppose it is the earlier wind up & screw type. (Same as my 2007 DR650 in fact.) When we stuck a finger into the open (tensioner) hole, we easily pushed the shoe in and thus removed all the slack on the chain. Looking at the tensioner, we do not see obvious damage. The tensioner pin retracts easily via the little screw at the back/inside. The pin has some ("backwards/forwards") play at full extension - about 1,5 to 2 mm, we do not know how much is normal. Alec will take it to Colin's Racing tomorrow to get some advice.
XT JOE wil post some pictures.
Cheers guys!