Chainsaws

David,

See the attached photograph, the grease cartridge is shown in the picture, and is usually available in Home Improvement Centers that sell chainsaws, and also at some Tractor Supply stores. To use the grease cartridge, near the rivets for the sprocket nose you will see a small 1/8 " hole on one side of the bar, or possibly on both sides depending on the bar type, push the metal tip of the cartridge against the hole, and push on the back of the cartridge, one or two pumps is all it takes and you should see grease ooze out around the sprocket nose and chain. Its a good idea when you refuel and while the bar is warm to give it another shot. If you degrease your bar and chain when cleaning and sharpening your chain. Remember to clean out the dirt and degrease the sprocket nose too, Then put fresh grease in the nose sprocket, and re-lubricate your bar and chain.

Second Question, Needle bearings - I totally remove my clutch periodically, maybe a couple times a season and of course that would depend on your chainsaw usage. But its fairly easy to do, after the first try and takes less than 5 minutes. Then you can totally remove, clean, and degrease the needle bearing inside of the drive sprocket. I re-lubricate my bearing with EP-0 grease, But remember don't put oil or grease inside the clutch, just inside the needle bearing. You could also just use bar/ chain oil to lubricate the needle bearing but I would be a little careful with where your putting the oil, Again Do Not get oil or grease inside the clutch, that needs to remain dry and clean.

Oh also, when completely cleaning a needle bearing remember to Inspect it, I have found bad needle bearings with broken needle cages that needed to be replaced, the bearings are also very reasonable ( like $5.95 or less), so I always have a few on hand for replacements, I can also use the new bearing as a gauge for wear compared to the old bearing, and if its starting to wear out just replace it. The drive sprocket bearing and clutch are very important to insure your chain is working  and driving properly.

I hope this helps.