There are two types to choose from: Windjammers, frame mounted, OOP since around 1981, but can be found on C-List/e-Bay; and modern, fork-mounted clear Plexi-Glass windshields.
The fork-mounted units will catch the wind, and apply its force to your handlebars, "helping" you steer your bike -- really only bothersome in high-wind conditions, but it can add a lot of strain to riding in high wind conditions. Many M/C suppliers sell these types, which can easily be adapted to fit an 80's model bike -- they connect to the fork tubes the same way as a modern bike.
The frame-mounted Windjammers, transfer all of the force of the wind to the bike's frame, which still affects handling in high winds, but you won't feel/fight it anywhere near as much as the fork mounted units. The Windjammers were incredibly popular in the 70's-80's: they provide tremendous protection in bad weather, a bit stifling in hot, calm weather due to limited air flow; they offer some storage space in the pockets on either side, and some models include built-in turn signals; they have a knob above the gauges, just below the windshield, to allow you to adjust your headlight aim up/down while sitting on the bike, making it easy to dial it in; the built-in headlight is a standard 7" automotive headlight bulb, sealed unit, replacement cost for a Halogen is around $12. The mounting brackets can be a challenge to find, but if you can weld, you can make your own to fit your bike. Craig Vetter, designer/founder of Windjammers and the Vetter Corporation, runs a web site to support the old line, as well as providing information on them for users/restore'ers:
http://www.craigvetter.com/pages/Vetter_Fairings/Vetter-Fairings-main.html. You can see some photo's of what they look like on CB750's on his web site (photo's of owners bikes equipped with Windjammers). Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII
Locked
I think all windshields look stupid. At least on motorcycles.
