Did your throttle grip look like this? How did you get the HND31 to fit?
I have a 2013 Honda Goldwing F6B Deluxe
The included instructions do not match my install. I did not see any mention that this would not work with heated grips.
Here is what my grip looks like. Old one is on right and is smaller than the HND31S. The hole in grip is too small for HND31S.

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