So , a couple year ago I put a pair of 12 light weight dirt-bike shocks on my S-40 .   They have been slowly getting weaker ever since.

The 12" shocks push the swing arm into the lower area below center of the swing-arm pivot.   When compressed the swing-arm arks up and increases the distance between pulleys , making the belt get tighter.

This year on the way to Lancers I had a full load of gear ... enough so that the swing-arm spent a lot of time tight-ing the belt  with ever bump .    

So , I said all that to say this :   I lost a couple of teeth off the belt ...
I had a spare belt to put on - but ...
I could feel the belt resisting the swing-arm movement with the shocks moving up and down on the larger bumps and if it had been much worse I would have stopped and loosened the belt a little ... but fact was the belt was already loose on smooth flat roads.

The Swing-arm being that far south of center wasn't good.

so :     Thanks for the tip Versey !  
VS700 VS750 VS800 INTRUDER S50 BOULEVARD 11" CHROME BOBBER SHOCKS