![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2012/10/full-2772-8101-scott_bonnar_590_belt_drive.png)
This is your belt drive, from your post. It is a normal Scott Bonnar 590 drive.
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2012/10/full-2772-8103-sb590_drum_clutch_control.png)
This is your clutch control cable. I can't tell from the picture what it does at the lower end. It is presumably operated by the squeeze-handle on the handlebar.
Please post some pictures to show some detail of what the lower end of the clutch control does. It could operate a standard SB drum clutch, or it could operate through a bell crank to tension the belt drive. We discussed this question in a previous thread some time ago, without finding out the answer.