kawasaki kz1000 shaft front brake problem

I have a KZ1000E1 and replaced the brake lines with ss and a new master cylinder about 2 years ago, been riding the my rig and it always stops OK. Parked it in the barn about 3-4 weeks ago and when I went out today there was no lever pressure on the front brake. there is fluid in reservoir and no leaks anywhere. Anyone know why this happened and should I just redo the fluid or does it look like I need to rebuild the cylinder? It's aftermarket and I wonder if the Kaw rebuild kit would work. Bought on e-Bay from a company in Florida and am having trouble locating their address.

Might be time to rebuild the mc.

Try bleeding it. Sometimes some sludge gets into it. You might take it apart and clean it with brake fluid if that doesn't work.
Steve