What brand chain? If chain is bad REPLACE!!! If it has aluminum rear sprocket REPLACE! On GSXR its VERY common to run the axle to the back of the swing arm. Also you need to make sure u are at 325-328mm EYE to eye on rear shock and your forks are FLUSH or a little down in the top tree. Moving the rear axle back makes the bike more stable DURING a turn,but harder to to turn in. Myself I am not decided on which way i like.