There are two different adjustments on the back of the '97. Pre-load is adjusted with the threaded collars on the top of the suspension unit above the spring. Ride height is adjusted by removing the front seat. You will see the bolt that attaches the top of the "shock" under a rubber boot. There is another nut on the other side of that one. To increase ride height you loosen the top one, rock the bike over on the side stand to take the weight off the rear suspension, then move the bottom nut up. When you are done re-tighten the top nut.
I have found that lowering the front 5 mm and raising the rear 5 mm quickens up the handling without inducing any stability problems. You can probably get away with more but I would approach it with caution.