Well i have drainned and refilled the roadking shocks, they use 10wt, belray fork oil exactly 10 oz. Just as CTS1950 said. I also got the info on doing this job and getting it right the first time. First, take out air fitting and turn upside down collaps the shock all the way down, several time (figure out a way to do this, i did) You do this till no more oil comes out. Do it a while and wait, then more. 2nd. turn shock over, and screw one of those rear end oil containers in the hole where air fitting goes, you know the pointed caps on round bottle. Cut bottom of bottle off like a long funnel. pour in adout half the shock oil, then collaps shock again several times to burp out air and oil will drain in shock. Takes a few times to get it in but you dont spill any and you know there is the right amount in there.
Put the air fitting back in with teflon tape, your done. Now I havnt installed them yet but i was told they will work better than new. Ill get back to ya when my swingarm gets here and let ya know how they ride,