I didn't have to when I put my Kuryakyn ISO grips on.  The end caps just pry off and you have a couple of choices on the grips removal.  Some folks just slice it with a razor and pull it off.  I slid a thin screwdriver all the way underneath mine and then just rotated it all the way around to dislodge the adhesive.  Then they pulled off easily.  The throttle sleeve had some ridges on it that needed to be removed.  I just used a wood rasp and filed 'em down pretty easily.

its part #1

When you get your new throttle sleeve be careful. What you acutally bought was the full sleeve with the rubber grip and chrome accent ring (yeah $35 is what I paid too  ).

I broke the sleeve on my Intruder doing nearly the exact same thing as you did (except mine got stuck on the lands). The sleeve has lands (raised ridges) on it and the rubber part has gooves that mate to the lands.

I did as Savage_Rob suggested and used a fine diamond file to slowly work the lands down. (some use a razor blade, but be very careful if you go that route...someone always seems to get cut   )

When I was trying it on to see if it fit (didn't want to take too much off) I used a water based lubricant (no comments...I use it for other things in my shop too  8) ) and put a little on the throttle sleeve and inside the grip. This way it wouldn't get stuck on the new sleeve while checking to see if it fit.

The reason I used a water based lube is because it cleans easily without leaving an oil based residue.

Once I had enough off I cleaned the grip and sleeve and very carefully slide it up on. Since everything was new I did the filing and fitting with the throttle sleeve off the bike. To me it seemed easier that way.

Anyway good luck with the new grips  

i use cheap hairspray as a lubricant putting them on then when it dries its like glue and you dont need to mess around with glue, i wittled min down to be smooth using a dremal with sander atachment