A common problem with vintage British bikes, due to their dry crankcases and remote oil tanks, is wet sumping. Wet sumping is when the oil from the remote oil tank finds its way into the sump of the engine. In this How-To we’re going to show you two methods of curing the problem as it exists in Norton Commandos.
Both of these methods involve changing the timing cover to incorporate a check valve on the pressure side of the oil pump.
One method is to replace your stock timing cover with one from the MkIII Commando of 1975 and the other is a modification to the pre-MkIII cover that accomplishes the same thing. We’ll detail the differences as we go along so you can decide which method to use if you should want to modify your Norton.
You will need the service manual which is available online from many sources, along with some gaskets and seals. Those are available from many sources, including our advertisers. Let’s get started.
— Keith Fellenstein
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