'75 KZ400 Rocker Arm and Camshaft Pitting

Hello to all, I picked up my first project bike, a '75 KZ400. I'm new to the scene so I've been doing a lot of reading. I'm currently in the process of removing the head and cylinders to repair the well known cylinder head leak. Upon disassembly I found some severe pitting on one of the rockers. It's enough to where it actually damaged the camshaft face as well. Bike only has a total of 8,000 miles.

My questions is this: Is this a common issue on these models? If I replace the rockers and camshaft are there certain part numbers I should look for or some to steer away from? I'm hoping if this was an issue, that it was resolved and the old part number possibly superseded. Please see below picture.

First I've seen pitting on a KZ400/440.
What does the oil look like?
What was the valve lash?


.

Hi. Thanks for the reply. Unfortunately, I did not measure lash before disassembly. The engine oil actually looks pretty good. The inside of the engine is fairly clean too. Cylinder walls look nice and are smooth. It could be an automotive oil though without all the good zinc and phosphorous additives for camshafts.

I've found all the needed parts except for NOS camshaft 12044-009. I'm having a hard time finding that.