If you take the cap off the reservoir be sure to wrap the reservoir with a rag and make sure everything around the reservoir is covered with a rag or two. You do not want any brake fluid to hit any plastic or painted surfaces. If any does, clean it up immediately.
I took mine to a local dealer to get the brake recall taken care of last year. They would work by appointment, so at the designated date and time I rode down to the shop. Unfortunately it started pouring down rain about a mile into the trip. A half hour later when I arrived at the shop I was soaked, and it was still raining. The mechanic did the recall, but they got me for tires and brake pads, front and rear. Not the free recall I thought I was going to get.
I rode home in the rain and of course everything was wet when I left the shop and when I got home. A couple weeks later I went to ride the Wing and noticed spots all over the fairing pocket, it had even splashed down on the chrome side cover and blown back on the side of the trunk on my ride home. That's when I realized the mechanic was sloppy with his brake work and brake fluid had splashed many places. When the bike was soaked in the rain I didn't notice anything. So now I have a whole lot of parts that are ruined, and not the beautiful bike that I took to the shop.
The worst part was I tipped the mechanic $50.00.
I really hated to take it in for the recall because nobody ever touches my bikes but me. I figured what could go wrong, it's a Honda dealership that's been in business forever? The old adage, if you want something done right, you better do it yourself really applied in this case.