Need to tighten the timing chain

Why do you want to do it, but if you do, To change it, Engine off, top cylinders off (slowly - when going up with cylinder top, look for 3 tappets and shims), side covers L/R off, chain tensioner out, metal sleeve at spark plug unscrew, (this is main part - you can see the details, just go step by step .

You can also check, if chain is bad, if you take off upper side cover on the top of cylinder (it is a small cover on each cylinder, on the side, if you up it 5cm, on the right side you see the top of tensioner, and a metal indicator, if this one is 10 mm out, chain is bad, if less, your fine. (in this case Engine is on frame, just take of the Tank)