I have an optronics brand compass that is liquid filled. I think it is intended for marine applications. Not certain, but I think it came from Wally World, inexpensive. Found a size that fit perfectly in the space just to the right of the key slot for the right fairing pocket. Mounted with velcro and still there after about 10 months. That location works great and the compass indication is steady and accurate enough for my needs.
Previously had one mounted on a dash panel on an ST1100 and it was always in motion, not very useful.
Sonny