Throttle Grip Sticking

[Lope]

I've installed new handlebar grips.
The one on the right is a bit tight. It was tough getting it on. I had to use soap and water, cut the end open and shove a screwdriver down the side and rotate it around the bar to slide the grip up into place.
The problem is the rubber from the grip is gripping on the handlebar (after the throttle ends) so the throttle doesn't auto return.
I'm thinking I need to maybe put a piece of plastic in there inbetween so it can slide, or some oil?

Do you have any tips?

[superlite]

I'm thinking I need to maybe put a piece of plastic in there inbetween so it can slide

Cut a piece off an old throttle tube if you have one, otherwise any suitable sized tubing will do. I'd avoid the oil fix though - it'll probably get gunked up and be worse.

[Lope]

Ah cool idea.