Dégagement entre le guide de soupape/vannes 16H

Is this on a WD type 16H with grease-lubricated valves, Francis ?

I've had problems in this area. I'm now running plasma-coated G&S valves (which I highly reccomend) with stem to guide clearance of .0035" inlet and .0045" exhaust and it seems to be working - Don't go too tight on them. Norton don't seem to have ever published a figure.

Russell Motors can supply the valves or they are available direct I believe.

http://www.gsvalves.co.uk/