I am reassembling the cylinder head on my 1972 Commando and I notice that if the slots on the rocker spindles are lined up to fit the retaining plate, the oilways are blocked. Conversely, if I line up the slots to clear the oilways the retaining plate no longer locates properly.
I suppose the oilways are supposed to be blocked as the bike ran with the retaining plates located for at least 50,000 miles, but I'd appreciate a sanity check please.
Slots at the end of the…
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Rocker Shaft Oilways
Only seems to be an issue with the exhaust rocker spindles on both of my Commandos. Inlet sides had no restriction.
I ground the upper slot on both exhaust spindles to clear the oilways and give a clear run for the oil feed to the centre of the rocker spindles. Still enough of a slot left to engage with the cover plate and prevent rotation.
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Hi Eddie . your photo…
Hi Eddie . your photo appears to show rocker spindles with oversize slotting and slots not in a position to be secured by the end covers ?.All not good ??
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They're all like that sir...
Thanks for the feedback. I made a tool that would allow me to get the slot perfectly aligned, just to see what the situation really was. As with Eddie Cross the oilway on the inlet (both sides) is fairly well aligned and the exhaust oilways have a little less than half the hole covered. (see attached images) I'm going to assume that's OK.
I'd like to think this was a clever way of restricting the oil flow to the exhaust spindle, but I suspect that (like many Commando manufacturing 'features') it is a tooling error. How did they drill those holes anyway?
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Mine is the same
Hi Matthew. For your peace of mind, mine is exactly as your photos show. I just rebuilt my head too and noticed the same thing and had the same thoughts as you. As the issue always seems to be too much oil to the head and the draining back of this oil, I thought as long as the hole wasn't completely blocked it should be OK and it is. I've only done 300 miles since the rebuild but I'm sure it's not a problem. I did find though that the spindle alignment plates are so badly made that they are all slightly different and alignment can change depending on which plate you use for which spindle and which way up you assemble the plate.
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Not really an issue?
Unless the head drilling is so restricted that it flows equal to or less than the hole in the spindle flat, then it is not an issue, because the spindle hole will be the controlling flow restriction.
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Slots at the end of the rocker spindles should be parallel to the gasket face. In this position the tabs on the retaining plate should locate in the slot and the oil drilling in the head should be visible. The flat on the rocker spindle faces the valve.