Oil leak from cylinder head nut?

Good morning all. I planned to take my new (to me) 1970 750 Commando (sn 138xxx) down the highway for the first decent run since I took delivery about a month ago.

The bike had been sitting for a week since I had started it last, so I drained the oil from the sump and refilled the quite empty oil tank to the correct level.

The bike started ok after a one loud misfire pop. Almost immediately, I noticed a steady stream of oil from the right hand side cylinder nut (one of the two recessed nuts). I immediately turned off the ignition. Oil doesn't seems to be coming from anywhere else i.e. the head gasket.

I don't have a box wrench to check if the cylinder nut came loose, either on its journey from South Carolina to North Africa (road and airfreight), or from the few short rides I have taken around the block. The box wrench and new washers are on order.

My question is: has anyone experienced this type of leak? Is is possible that the cylinder nut came loose? Is is a matter of retorquing the nut in question (or all cylinder head nuts in the prescribed sequence).

It seems strange to me that the leak is so localized. I'm a new Norton owner, so perhaps I should get used to this type of occurrence. The previous owner tells me the bike went through a resto in the 90's and had "run well since". It was his daily rider so perhaps, this issue has resulted from a month in transit with the bike not being ridden much over the last two months.

Any thoughts and advice welcome both as to cause and how I should go about fixing this problem.

cheers, Joe

Check your oil line to the head at all the fittings and banjos. This can be deceiving and a crack, usually where the tube connects to the banjo, are not visible but when the RPM's come up hot oil will spray on to your leg. At idle it will be a slow stream that runs down the fins and appears to come from the head bolt.

or you may have a composite head gasket that gave up the ghost. simply torquing this nut down will Not Help. if you do decide to tighten This nut, don't go beyond the torque specs and check all the nuts and bolts on the head with a torque wrench.

Got it in one. RHS oil line feed nut to cylinder head was loose. Problem solved. Thanks.