Oil pump lapping

1970 750 S . I am putting bike back together this weekend and thought i would lap the pump before i fit the timing case as i have wetsumping issues like most others. I have a couple of questions if you can assist please. The pics below might help .
There was no gasket or material between the pump and the crankcase where i have read there should be something?
What should I use?
What does the grommet do? mine is a bit tattered and worn, does it affect anything. Can i take it out and refit it asit interferes with lapping the body.You may be able to see by the coloring of the faces that things have not been seating flush, Would this agravate the wet sumping I wil be lapping the surfaces anyway but thought maybe a sealant on the end covers might help? I have read about priming the pump after refitting it , how do i that

Hi.
That little grommet seals the pump output to the timing cover and on to the crank bearings so it's under full pump pressure! I would replace but if it's not split you can re-use temporarily. They look tatty cos they're squashed tight between pump and cover. It will come off easily and you may find the tube insert it sits over will also come out.
There should be a thin paper gasket between pump and timing case. It's only about 003".
You can prime the pump by making sure it's full of oil when refitted and unless you are desperate to start the engine let it sit overnight or at least a couple of hours and the oil will find it's way into the pump. Some talk about filling with Vaseline but it's not necessary with a gravity feed.
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