Need some help

So anyone else extend their risers on the handlebars and then have that space between the bars and base that the steering neck comes out of? I forgot to even compensate for this space that will be created. To try and keep snow and possible water out of this area I need to come up with something that can fill in this space. If you have any suggestions and pics of what you came up with please let me know. I was thinking maybe some pipe insulation would work since its round and easy to work with may work but the diameter is an issue. I would need something about 4 inches around to take up most of the space. I don't know if there is a new handlebar cover that I can buy that extends down to the base.

Thanks

Need some help