If you¹ve bought a used bike that¹s over five years old and it rocks back and forth even when you¹re feathering the brakes chances are the fork springs are more than a little tired.
Fortunately there¹s plenty of choice out there, look for progressively rated springs as they are more able to soak up the small bumps and cope with heavy braking too.
Makes like Hagon, Hyperpro, Ohlins and Progressive Springs all supply kit. Armed with them and some fresh fork oil you should see a transformation in the front endon your bike.
The only problem there could be that you'll enter the suspension spiral and start to feel the rear end needs uprating.