my 80 goldwing has a sight glass for engine oil level. there is a little screw that turns a "wiper" to view level accurately! i'm building parts washer at this moment and i think sight window with 10"x12" with a crank wiper is the way i will go.
in 82 i had mine right inside the door so when i returned home from work i could raise garage door and grab a cold one before entering the oven. never got much done except drinkin' and thinkin'! 83 to the rear because all my broke friends were there wed.,thur. the 90's in middle of solid...