More tell tale signs

‎The rocker box cover above the exhaust valve has plenty of oil on it, to the bottom of the image, but above the inlet it is clear. Close examination shows 4 sets of tiny holes under the valves. My idea is that these are oilways to the valvegear. Looks to me that oil is going past the exhaust valve, some burning off to produce the sooty spark plug and some blowing back up into the rocker box. More turning over of the motor produced more oily sludge on the exhaust valve stem so it looks like the head has to come off for new valves and guides.

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