Thanks, would be a similar case.
Disassembly is impossible, however there is an opening in the back to access the edge of the dial. There is a gap with the side to inject and retrieve liquids using a syringe.
Vinegar suggested is easy to rinse out.
Thanks and good luck too!
Was not supposed to be a restoration project, bought the bike after 30 years not riding. A now or never moment lasting 3 years so far.
Had new tires put on it and ended up with a leaky rear tire valve. $150 to replace.
Had the valve replaced at another Honda dealership, was suspect of having no weight for balance.
Tested myself and found an imbalance. When asked to redo, a 7.5 g weight was placed. Said they don't put weight if less than 10 g!
I would not ride a modern superbike with up to 10 g wheel imbalance!
So, doing it ourself is way more fun and reliable!