Suspension question

First, I would say if you have a shop in your area who are suspension experts, that's by far your best bet. But if not, here's some info to get started for a weekend experiment. The spring rates shouldn't be too far off from you at ~170 lbs. (12 stone) so first thing to do is get the spring preload set correctly (aka. "Set the sag"). If you don't know how to do that, just go to YouTube and search on "setting sag" and you'll find lots of help. You'll need two helpers and a measuring tape. For general street riding, aim for about 40-45mm of sag in the front, 35-40mm in the rear. Don't worry about setting the free sag (just the weight of the bike) just go straight to setting the sag with you sitting on the bike and get it in the range I specified above. We'd run less for the track, but for the street that should be good. Once you have the sag set, go for a ride. If you took some preload off from the stock settings you might find that this improves the ride already, if you didn't change the preload much then you might not notice. Next if the bike is still feeling stiff, you need to determine if it's the front, back or both that are feeling stiff. Go for your ride, over some bumps, and try to pay attention to the sensation you get through the handlebars and through the seat. When you hit a bump, are you feeling it harshly in your hands, your bum, or both? Only adjust the end of the bike that is causing problems, or both if both are causing problems. Start by removing 3 clicks of both rebound damping and compression damping. Go for a ride again, if it's better, stick with it. If it's still harsh, take 3 more clicks out. If still hard, try one more round of 3 clicks out, but don't go any farther than that. Ideally we'd be trying to balance the rebound damping to the spring preload, and then tuning compression based upon travel used and rider feedback, but that's a more advanced topic best done by a suspension tuner who's got hands on the bike.

the german PS magazine did a comparisan 899 vs. GSXR-750 and tested the bike on the road and on the track.

they published a setup which I (5 ft 7 in, 12 stone) found very useful on the road:

front fork:
static negative spring deflection: 36 mm
compression stroke: 7 turns open (stock: 7 tunrs open)
decompression stroke: 6 turns open (stock: 5 turns open)
no further changes

rear shock:
static negative spring deflection: 13 mm
compression stroke low: completly open (stock: 3,5 turns open)
decompression stroke: 13 clicks open (stock: 15 clicks open)
no further changes