What is the easiest way to remove the stock grips from the handlebars without damaging them, so I can reuse them on the new handlebars?
There isn't an easy way. The left side just takes some caution. The right side will require destruction if you want to use the throttle sleeve for the new grips. However, you can buy throttle sleeves and grips with the sleeves if you look. This is the easiest way.
Check the accessories area of the web site.
http://www.VulcanDrifterRiders/reviewpost/showcat.php/cat/24
Cheers.