Howdy! You're probably going to get more constructive feedback from this forum:
http://www.cb750c.com/The original bearings on the earlier bikes were only sealed on one side and could, in theory, be repacked but to do it properly the bearings must be removed which usually damages them.
I don't know if the DOHC's used the same bearings. If the DOHC used bearings that are sealed on both sides they aren't serviceable anyway.
Ideally you are going to want to replace the original bearings with new bearings that are sealed on both sides.
You can probably do both wheels for less than $50.
All Balls sells complete kits, they can probably fix you up.
http://www.allballsracing.com/It's good that you are looking at the wheel bearings, I think a lot of folks overlook wheel bearings when they're servicing or resurrecting an older bike.
New wheel bearings are one of cheapest and most important things you can do to make sure the bike is safe.
