Originally Posted by waztafel
ok. So is this an expensive problem?
Here is a Link
. IRRC, the 2000 F650 don't have ABS (correct me if I'm wrong). So, it should be easy to get to. In any case, sitting on the bike, the tensioner is located on the left hand side behind the cylinder. At least on the '06 models, it takes a 22mm wrench. If you have ABS, it's a PITA to get the wrench in there and get loosen/tighten the screw.
If you do it yourself, the complete tenisioner cost around US$ 70. Look at this Link
, go to section 11. Engine
and next to sub-section Timing Gear Cam Shaft/Chain Drive
item 8 and 9 make up the new tensioner. However, read up the first link and see if the tensioner needs replacement or simply a little re-installation/adjustment. Hopefully, the chain guide is not worn out. Not a big deal but more work...
Found a pic of my '06 with the valve cover and cam-bearing-bridge off. If the chain-guide is bad, then this is how far you need to get into it.
But, you'll find a whole slew of good info on The Chain Gang
to guide you through the process - if that's what it takes.
I hope this helps.
"Hey, ...I'm just ridin' shotgun"