superchode,
There should be a seal at both ends of the swingarm tube sounds like you're missing one. They are steel with a double rubber lip seal inside. While you have the pivot bolt removed pull the original zerts and clean all the grease out of the bolt hole so you can completely remove any metal fillings from tapping the hole. Just find an appropriate sized small threaded grease fitting and thread the hole to suit. You may need to enlarge the hole slightly first, it depends, there are lots of different sized fittings available. When you refit the arm you can't have too much grease in there the bolt will just push it out, so lightly lube all contact surfaces, adjust the nut accordingly, and when the tension is right grease both ends with your gun while working the arm up & down until you see the grease just start to escape the seal. Leave it at that, don't over do it the grease will probably ooze out of the seal the first few miles of your first ride. I have the grease gun the dealers ended up with from Honda I quess, but it's an oldball, newer style fittings are far better.
Good luck, your swingarm (and your ass!) will thank you!