Painted black

Theere is no need to put anything on if you vapour blast, or as it's sometimes called aqua blast.  The original looking shine will last for a very long time....years.  Blasting seals things up, which slows oxidation.  The photo below was taken shortly after the engine was blasted and reassembled in 2018.  The photo below that was taken 18 months later.  The shine is still there  today.

Reassembling Engine Winter of 2018
 

Photo taken spring of 2020
 

That's a really nice bike HRM 

I wasn't planning on taking motor out the frame  trying to clean it up the  best i can but will check around for vapor blaster in my area thanks for the pictures  real nice bike I also have a 74 z1a mostly original second owner

Wookie58 wrote:

That's a really nice bike HRM 

Thank you Wookie!  It's my nostalgia bike.  I bought one new in 1975.  Sold it in 1987 as I had to spend time with kids growing up.  I bought this one in 2014...mostly original except for seat and pipes and a few nuts and bolts.  But this one is my favourite rider.  I've since put a '78 head on it and '76 carbs.  

 

Pattonrd, I don't think you can vapour blast an engine in the frame.  It really needs to be torn apart to be done properly.  It's amazing how much dirt gets into the cooling ports on the barrels and head.