I was changing my valve oil seals (exhaust only) on my 2000 yz 426, when something terrible happened. I was using the valve spring compressor to remove the valves when me and my clumbsy bear paws chipped a peace off the valve (combustion chamber side) . Now I know the 2000 had steel valves but is the valve coated with something to protect it cause if its not ill just polish the valve head and be on my way. But it looks like i took off some kind of metallic crust off. I guess i'm an idiot for using an automotive spring compressor !WAY TO BIG!