The dots need to face outwards and be on top. The oil gallery is angled to flow oil from the oil route around the top stud into the needle bearings in the rocker arm. If you have it the way round the oil gallery doesn't work and you end with a reduced oil flow through the bearings.
I see on the pictures that your bikes a V reg so may be a 1979 or 80 model. Are you running points? They sit under the front engine cover in what's known as a "Bean can" and may be the source of you problem.