I am restoring a 1983 DR500. Didthe top end and cleaned it up. Fix the dentedtank . Recovered the seat.Painted marrone with gold flake. Lots of detail. The rear shocks have a small cyclinder attach with a 6" hose. Is the small one supposed to be filled with nitrogen? Does the dealer fill them.---------How much oil is supposed to be in the shock? Looked everywhere and cannot find any imfo. The number on the shock are a discontinued Suzuku. Thanks for the help.