On the pre-1975 SOHC4 bikes, the swingarm bolts had Japanese zerks on the ends of the bolts and gun-drilled passages 2.4" deep into the ends that are cross-drilled into the collar to directly center-feed each bushing. This superior system works very well when delivering grease...if you can get it into the fittings, or if they don't pump out of the bolt in the attempt.
You can drill & tap the bolt ends with an Irwin tap-and-drill kit from Ace Hardware (#10 drill, 1/4-28 tap) and install North American 1/4-28 thread straight fittings on these early arms easily. After drilling and tapping, carefully pick out the chips inside with a small wire before installing the fitting (I do these almost every week!).
On the post-1974 bikes, it is a very different story. They have 1 grease fitting in the center of the arm, with different bushings and seals and collar, and if the old grease EVER dries out inside, the new grease will NEVER reach the bushings (and truth is, not much of that reaches them in any event in this setup). The only way to effectively grease these 'arms if the bike has been sitting for a long time is to disassemble the swingarm, pull out the collar, clean everything, hand grease it, reassemble, then pump it full of a modern, thin, all-purpose grease so as to keep it from drying out again. And often, like every 3000 miles. (Whew...). Or, you can just convert these over to the earlier system, which is the only one Honda sells parts for, today, anyway. Except their current bushing offerings are steel, which will destroy your nice new collar in about 5000 miles.
Or, if the bushings are worn out, you can pull the arm off and send it to me and I'll rebuild it into a Lifetime Warranty situation for you with custom-fitted Oilite bushings, but that's a story for another day...