There are two ways to grease each of those bearings; grease needle or repack.
Purchase a grease injection needle from an Auto Parts store. Remove the speedo drive cover, insert the needle by feel through the very outer edge of the rubber seal on the bearing and as you're gently inserting it, feel it go inbetween the ball bearings. Grease very easily as the end of the needle and the fitting of the gun will seperate if you squeeze to hard. Repeat this in four different spots around the bearing.
Another way to grease it is to remove the rubber seal on the bearing. It's fairly easy to pry it off. Once it's off, inject grease into the bearing and push/work it into the ball bearing with your finger. Replace the seal when your done. Be careful not to bend the seal as it is a thin metal ring sandwiched under the rubber.
Using the needle, you'll be suprised at the amount of water drips that flow out of the bearing after each trip (500 miles or so). Both methods will suffice at keeping your bearings corrosion free.
There's no need to remove the secondary while greasing either bearing, although the airbox must be removed when greasing the jackshaft bearing.
Because I did a track change this year and the bearing was removed, I replaced it at 4400 miles. It still looked new and rotated as new. I've greased these religiously after each trip and always displace moisture when doing so.
Jon