I've just put mine back together after top end rebuild and had the head, barrels and engine covers all high pressure water blasted. They came up like new and the old timer who did the job said not to put anything in the way of clear on them - just wash with water occasionally. Not on the road yet so yet to see how it holds up. While we're talking engines, can anyone tell me what this is - see photo of tiny ball bearing like internal revealed when I scraped what I thought was old paint off front of engine. There are four of these across the front just under the cylinders. Thanks, Slug.