| I guess the manual will tell you to adjust the chain whilst the bike is one the side stand, as not everyone wants to go out and buy a stand.
The amount of slack is measured at a midpoint along the underside of the swingarm. I think the bikes came with a sticker marking this point???
Anyway...the chain should have about 25mm of play at this mid-point. When it is then stood upright, and the suspension sinks further, the chain tightens more, and when the rider gets on...it tightens still further.
But if you had the right amount of slack when it was on the stand, then it shjould be correct when the rider in on the bike also.
I was always told thast Ducati 748/9** like the chain too loose rather than too tight?
Also note that when you do adjust your chain, you are immediately adjusting your ride height also due to the eccentric hub...this is unavoidable.
If you like how your bike handles now, make a note of the ride height before fiddling! | 
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