Hey LTGTR-. The plastic reservoirs are non-serviceable and therefore not replaceable, you have to buy the whole unit which is no longer available from kawasak Canada as I found out last year. I ended up finding a nice Honda front brake reservoir at the bike boneyard that I swapped in. It looks almost identical including the round cap of the '77 650.
Cheers-Colin Firth-Ontario Canada
'77 Kz 650 Custom - (Miss July on 2006 Kzr Calendar,) Newest rebuild includes...Wiseco 810 kit, Kz750 cams, Kz750 intake valves, 750 GPz springs, Ported head, WG Mikuni 28's, Filters, Dyna Ignition and coils, MAC pipe, 14 tooth sprocket, going back to original '77 Moon Dust Silver. Goal is to have a stock-looking bike that will tighten up any loose dental fillings off the light.
-1977 Kz650 Custom bought new by brother. Now with 810 kit, GPz750 cams, intake valves, Mikuni 29 smoothbores, velocity stacks, Dyna Igntion, MAC pipe and other goodies.
-1982 Ferrari 308 GTSi Red/Tan
-Toyota FJ Cruiser - 6 speed tank
-2010 Mazda CX-7 Turbo (my bride's)
-1998 Jeep TJ Wrangler 4.0...
