I want to get some new grips

Go to any bike shop and you can find a good pair of replacement grips for $6-12. You should be able to find some that are more comfortable than the stock ones. eBay usually has a number of dealers selling grips, too. The Pro Grips brand is quite popular among club members, as are Oury Grips.

A lot of members go thru lots of work drilling, hammering, even using dynamite to remove the bar ends in order to remove the oem grips. There's really no need, unless you plan to keep them (but why?) because you can easily cut them off carefully with a razor blade, then slip the new grips on with soapy water or hairspray. Another reason to cut them off is that some are glued on. There have been reports of one side being glued on, while the other isn't.

To remove: Take a razor (or sharp utility knife) and cut off the old grips from the bar up (that is, do not cut down into the grip; work the edge of the razor under the grip, and cut in an upward motion, to avoid scratching the bars).

Then take your new grips, and apply a little soapy water to the inside of the grip and to the bar itself (you can also use hairspray, should you have some Extra Super Hold left over from the 80's). The soapy water or hair spray will make it easy to slide the new grips on, then after a few hours will dry to leave a good seal that will keep those grips stuck on there. Some members have reported slippage using hair spray, although most haven't. If you have some spray adhesive around, that would be a good alternative.

Notes:

The left and right grips do not have the same inner diameter, so don't frustrate yourself trying to get the left-hand grip onto the throttle; it won't fit. The diameter of the bar and grip is smaller on the left side, but the bar end is the same size on both sides. It may be difficult to get the grip over the bar end on the left side because the bar end is much larger than the grip. A lot of soap and twisting should do the trick.

A cool trick learned at a dealership many moons ago is to use compressed air and blow it under the grip. Lift up the outboard edge of the grip, and jet some air under there. Working quickly, you can have a grip on or off in seconds, with no residues to worry about.