I picked up a petcock from my local Honda dealer for a 1994 CBR900R

Part# 16950-MWO-790 (Canadian Dealer)

Take off the screen filter and pull out the brass tube..use your hand not a wrench or you will cause damage.
Remove the same parts from your NSR petcock and insert into new one.
Screw on your old handle and there you have it!
A leak free petcock!