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Inlet valves

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pauliexjr:
Hi All, just in the throes of rebuilding the head and after de-coking the valves the tapers on the stems of my inlets are quite badly pitted. I've looked for new ones but they seem like rocking horse poo and the few I have found are incredibly expensive. I was thinking of taking them and the exhausts to my local machine shop and getting them turned down as I'm looking at a mild gas-flow on the head anyway. Any thoughts or recommendations?

Bryanj:
YOU CAN NOT re-machine the valve surfaces on the valve as they are not fully hardened, Which model is it as Dave Silver has most of them?

davepainter:
Hi a firm called jts motorcycles are currently advertising exhuast valves on e-bay at

pauliexjr:

--- Quote from: Bryanj on October 04, 2011, 05:01:03 PM ---YOU CAN NOT re-machine the valve surfaces on the valve as they are not fully hardened, Which model is it as Dave Silver has most of them?

--- End quote ---
It's a CB750 F2 sohc. I've looked on Dave Silver and can't find them, CMSNL want 77 Euros a pop! The actual compression-side surfaces are fine, it's the area behind the seat leading up to the stem that's pitted, and from my experience of gas-flowing Mini engines turning the valves down to a 'penny on a stick' is part and parcel of getting a better gas flow. Are you saying that can't/shouldn't be done?

Bryanj:
NO that definately should not be done if you want a decent life and undamged engine! Dont forget these motors already rev markedley higher than a mini.

If you go to our sister site in the US (SOHC4.net) and look up dynoman he does valves with smaller stems (along with guides to fit) and i bekieve standard ones as well. Also worth looking up Mike Riek as well as he gas flows the Honda fours incredibly well and has a wealth of knowledge as to what works and what doesnt

Have you checked the exhaust guides as the F2 is notorious for wearing them out very quickly

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