Most LED's are far dimmer than their filament counter-parts. Shop, and compare, carefully. They will also draw far less current, which will cause the blinker to malfunction. They will require either a different blinker, or some load resistors, which will draw more current -- this will defeat the purpose of using low-power LED's.
I would suggest searching the Internet for reviews, and comments on using LED's on motorcycles. There are articles which discuss converting, the issues, and pitfalls. Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII