Speed Triple 955 rear shock

I have an 04 955 with just over 12k miles on it, I have only done about 500 miles or so on it so far and am finding the rear suspension very stiff. I am pretty light at about 12 stone in my riding gear, I have backed the spring pre-load right off and it still hardly moves when I sit on it. I have tried loosening the bolts on the drag link and tightening them to the correct torque and it's no better. I met up with a mate at the weekend who has a similar bike with 40 odd thousand miles on it and the rear suspension is much softer even though he has a bit more pre-load on it. Is the rear shock on these usually so heavily sprung? The only thing I can think of is to strip the whole linkage down and make sure everything is free, which is a bit of a ballache, anyone had any similar experience with this?