If they are aftermarket shocks you will need to get some special tools such as a certain type of regulator that measures nitrogen a certain way to make sure it is accurate. If you plan on doing it the right way its much more effective to send it out unless you have the right tools and knowledge. otherwise you wont be able to have them done correctly.
2005 trx450-houser arms/PEP, 06 swinger, dc-6 linkage, lsr axle, protaper, houser stem, goldspeed wheels and tires, pro armor skids/nerfs/bumper,k&n, 43.5mm FCR, Kohashigawa Exhaust, +1 Ti Intake Valves, +2 Ti Exhaust Valves, CV4 Valve Springs, webcam, CT Racing Head, CB Seats, je 13.8:1, crf ignition, fluidyne radiator, hinson, asv, DID, Supersprox, ccp damper, Twist Throttle.