Courtesy of Big Sid and thevincent.com. You should peruse the technical topics if you have not already done so.
http://www.thevincent.com/vincent engine.html
Oiling procedure prior to initial starting : If the oil isn't already poured into the top member oil tank. Proceed thusly. About 2 & 1/2 qts will be enough if you follow these other directions. Then after running it a while, {even a brief ride twice around the block} do then. Fill to the normal level, ie about 3/4 inch below the filler tube. Check for leaks afterwards at Every banjo bolt, etc. Some loss by oozing is common, snug up as needed, but very carefully. Any faulty seal needs being replaced.
There are 4 things to do, important if rapid wear is to be avoided .
#1 Back off about 2 turns the lower banjo bolt at the bottom end of the large feed pipe, a pan beneath it. Wait till oil issues forth freely - not the early bubbles but a clear oil flow. When you see clear oil tighten the banjo bolt carefully { this to let the air column escape ensuring that oil is present at the pump entry port}. Tighten carefully so as not to fracture. Clean off the fittings.
#2 At the forwards end of the timing cover facing you is another banjo bolt - a longer one. Both hex heads are the size of a spark plug hex - 13 /16ths. When unscrewed slide this one out. Using a hand held oil pump can - enter its spout into the hole about 3 or 4 inches, this will project into the oil filter chamber - right into the center of the filter element. Pump this empty chamber full or nearly so to lessen the time needed to circulate the oil when started. Pull out the pump and replace the banjo bolt. Carefully tighten. Wipe away any spilled oil.
#3 In the center of the lower side of the big end feed quill is a small screw, remove and pump in several strokes of oil to flood the rod big ends. Replace the screw.
# 4 Remove the center 2 rocker caps. If they feel to jam Stop. Turn back inward - rotate the motor a bit to lower the rocker arm and try again. Now, refill the squirt can and pump its contents down both pushrod upper openings - 6 full shots in each one. Replace the caps. This will flood the cams and followers so they won't rotate dry, then the oil will run down into the sump where it will be picked up by the pump to be returned to the tank, oiling the rockers as it goes through the return pipe. If all this is done correctly you should see oil returning in the filler neck very soon after restarting. I'd guess within a minute.
#5 Check the gearbox oil level - should show on the bottom of the stick. If not add a bit more til it does. This holds a full quart from drained.
#6 Check the primary case level. Oil should be up to the level plug opening and just ooze out a little bit. Not drip heavily. If so let it drip till it near stops. Replace the short bolt and just snug up, careful not to damage the threads. This is a steel bolt in soft alloy and can strip. Sid 12/14/09