The automatic cam chain tensioner is present in all 650s and in some later 500s in some countries; it looks quite different to the manual tensioner, as you can see:
Looking at the end on the right in the above photo, you can see the ball which forms part of the mechanism:
This is the adjuster fully extended:
As you can see, if this hole is visible at all when doing an inspection with a mirror it’s time to change it as there’s hardly any distance left before you’re at full extension, which means bad things for your chain in the near future.
Here’s approx. the distance between the end which meets the cam chain and the beginning of the hole you see in the above photo:
