no oil flow or pressure

Hi, I’ve just fitted a 16mm oil pump to my mk2 le mans and when I turn thebike over I’m getting no oil pressure or flow, I’m at a loss to what is causing this as the pump tolerances are great and I’ve been really meticulous in the assembly of it, the oil pressure light used to go out quickly even though the pump tolerances were way out on the old pump, any help would be great, cheers chris

Does the pump need priming?
(Might be possible by squirting oil down the oil pressure switch hole.)

is the sprocket keyed to shaft if so is the key in place if woodruff type easy to push it out is it possible to fit the pump upside down on the casing have you had sump off to do filter if so is filter on tight

Cheers all sorted now, the filter was blocked, new filter and complete clean of the sump, job done!!!