Unfortunately the clean tank of the 1986 I got came with no petcock so I am in need of one to save me from trouble trying to adapt a 1985 petcock to a 1986 tank. I wouldn't mind if it is leaky as I hope I'll find a way to fix it. Donations are very welcome!!! I could also trade it with one of the 1985 (but I don't really know if it functions properly).
I suggest sending a PM to member Jamie Daugherty or looking up his contact information on his website Daugherty Motorsports - Motorcycle Suspension Performance and Modification and seeing what he can help you with.