XBR500 oil consumption

[welland99]

This one also rattles more than the others (cam chain) when cold.

Why would a cam chain rattle more when cold than when hot?  I imagine that it must be something to do with a component heating up and increasing the tension (reducing slack) - but what?  When the chain heats up, wouldn't that tend to lengthen, thus reducing tension and exaggerating the slack-chain-rattle?   

[johnr]

or else the tensioner blade might be on its way out and when it gets warm it has more flex in it so takes up the slack a bit better