I believe I have come up with a fix for the moisture problem in the spedometer on the FLSTC models. The first test went quite well, and I am making a modification to the process and will be rechecking. The moisture is being extracted using a vacumn chamber, then the chamber is charged with dry nitrogen. It appears that the nitrogen helps, but I am considering other options. So, if some of you scientific types have a suggestion for something other than nitrogen, let me know. Don

 

I don't, nitrogen is the accepted medium for fillingtelecopes, binoculars, riflescopes, etc. for the same reasons. I don't see why anything more "exotic" would do any better.
But the problem for you will be to keep the nitrogen in and the ambient air out. Speedos are not anywhere near as air tightas the scope on a hunting rifle.

As I see it the problem and solution have three parts.

1) Figure out how to empty it of air, that part you got with the vacume.

2)Fill it up with nitrogen, ya got that too.

But #3 is the real problem, Now you have to figure out how to KEEP a pound or two of positively pressurized nitrogen to make sure air (and moisture) can't get back in. Do that one and you'll have the problem solved, forever.

 

The little vacumn chamber works good for getting the moisture out. Charging it with nitrogen keeps any moisture from getting in once the chamber is open. As for how long it will stay dry, I don't know, but so far it has worked. Maybe it will be something I'll need to do a few times a year, or after a ride in the rain. Don