Hurray for the weekend! While having a nice "New Wave" playlist (click to play) playing in the HVC's workshop, I've put my Honda PC50 valves in the lathe and cleaned them up pretty well. The white "sediment" is always the hardest bit, but having the right tools is worth gold.
Up to today, I have actually no idea what that white muck is, but I'm sure it has something to do with the engine getting too hot. This engine probably has not gotten any maintenance from when it has been bought at "Cor Mantel - Rijwielen en bromfietsen" in Amsterdam, The Netherlands. I'm pondering if I should visit them, since they still are in business although only selling bicycles now.
If I want to make that happen, the valves need some proper grinding first. The valve seats are quite worn and most likely not closing well anymore. The cylinder head is soaking in a detergent solution as we speak, so grinding still has to wait a little bit. Until then, I need to finish another engine, so busy busy! :D