I bought this big from a guy a few months ago and he said his dad only rode it a few years.. The rear shock bumper is messed up and I've noticed the rear sits low when I ride . I weight about 170 so I have the spring collars all the way up without there being any play in the spring. It dosnt throw me off like it did before I adjusted the collars up and dosnt jump that bad but I Havnt tried any big air on it... The question is do I need to get my shock rebuilt? I know i atleast need a new shock bumper. From sitting on a stand to me being in riding position it has 3 1/2 sag... Any help?