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Certainly that is the case today and even silicon steel inserts in some cases but not always the case in the 60's and early 70's. I think the Cbx 1000 Honda used another variant, Sintered Iron valve seats, indeed these are favoured by alot of cylinder head refurbishers in the UK .Some cars and other older cast iron headed vehicles often had the seats cut directly into the head, Triumph straight six for instance and the Austin Healey 3000. The use of cast iron inserts in Triumph/BSA machines was often used on motorcycle heads as that was all that was required, why bother with anything harder when the lead in the fuel did the job for you? It was a cheap product and easy to manufacture.
I'm unsure of US regulations on unleaded and am sure that you are quite right with ref. to the US but certainly Benzine is a constituent part of UK unleaded, although it must be said that the oil companies deny that quantities are at a higher level now than when Leaded fuel was widely used.
Incidentally, I lifted a head off my old BSA B25 last night, it rained and is cold, left the head on the bench and the seats are covered in a fine film of rust this AM, a sure sign that at least they aren't Stainless ....But then again it is a BSA I spose!
Cheers
BonnieT
[ This message was edited by: bonnietiler on 2007-02-27 17:40 ]
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