Seized chain link!!!!!

Hey all,
Rescently purchased a 92 ZXR400 race bike. Pretty neat all round, but while cleaning the chain yesterday i noticed the chain link that is riveted (where it can be taken appart) has 1 link that is locked hard and cant be loosened! I can kinda get it to move a bit with pliers in each hand, but is hard work. The chain and sprockets look pretty good so im hoping that someone out there has a remedy that doesnt require a new chain... If all else fails Ill catch up with my mechanic after easter. So any ideas to loosen it ?
Thanks

perhaps a bit of penetrene/inox and a couple pairs of vice grips. just make sure you dont scratch the link on the chain too much, sideplate doesn't matter *as* much though.

Remove that link and replace it with another split link