So this screens the oil from tank before the pump and the main filter is for oil after it's gone around engine but before pump return to tank?It's not a filter, but a micro-screen strainer.
Yes, this prevents small bits traveling from the oil tank getting to the oil pump.
Mine had a few tiny pieces in it when I inspected ans cleaned it.
So it is needed.
Not quite, oil goes from the pump, through the filter, then to the engine components, then returns to the tank going through the cooler on the way.So this screens the oil from tank before the pump and the main filter is for oil after it's gone around engine but before pump return to tank?
The boys at Donington must have noticed something, and decided to insert a strainer between the tank and pump.
In wet sump motors, the oil pump in the sump normally has a protective screen in front of the pump induction.
The 961 is a dry sump design, but, I'm assuming Norton decided to do the same type of thing for the 961's pump.
It would have been nicer if the strainer had a better quality O-ring to avoid leaks due to misaligned O-ring.