Valve Spring Seats

[yamahaluke]

So i just reassembled my had last night after lapping the valves i took it to the machinist to have it hot tanked and today while I was looking through my clymers manual I noticed valve spring seats in the diagram of valve parts, problem is I do not think I had any valve spring seats when I reassembled the head, do not know if they got lost in the cleaning tank at the machinist or what. My question is, are the seats neccessary has anyone done without them. and does anyone know where to get them other then from some seriously overcharging internet supplier?

[CaptonZap]

You REALLY ought to put them in. The springs are hard, and the aluminum head is soft, and the springs will wear into the head. And, the spring pressure is reliant on the thickness of the washers to develope full spring pressure.
If nobody chimes in, I can measure one tomorrow.
CZ