I think the best thing to do is loosen the screws that hold the cam in place,each screw has a locking screw,so loosen the locking one first & then you can back the other one out 1/2 a turn,do this to all 4 & it should break loose.It would be pretty hard for any penetrating lube to get into the correct spot ,so this will work.Then of course you'll have to snug the screws back down & re-tighten the lock screws b4 you run it.It looks like your machine has allen screws in it.