The safest way for you is to get an owners handbook from the VMCC Library and follow the makers instructions. They are on line at
www.vmcc.net You should also get a spare parts list for it as well so you can check that everything is as it left the factory. It is important to be sure no one has altered or removed parts of the pumping system so that the system works as the maker intended. It's amazing what can happen to a bike that has been around for 80 years or so.
Assuming all is as it left the factory the general advice for all total loss systems is to adjust the drip feed until the exhaust gives off a smoky haze with a distinct little puff when you blip the throttle. This is fine for an engine built to original standards but if it has been rebored since new the chances are it has had a modern oil control ring fitted to the piston so it won't puff smoke no matter how much you increase the oil. In this case all you can do is count the drips in the oil feed. Start off with a generous 50 or so drips a minute and cut down a little at a time if the road behind you disappears in the smoke. Just remember over oiling causes less problems than under oiling and is cheaper in the long run.
You don't need to prime the engine with several pumps of the handle before you start, and how often you operate the pump can depend on how much oil is in the tank. Any straight 40 or 50 grade oil will do. Multigrade oils are pointless as the oil is pumped in, gets used and is thrown out. Personally I use a plain two-stroke oil as it is a straight 50 base with various additives to keep the internals clean. Stick to the same grade as every time you change the oiling rate will change with it so you have to start afresh.
Have fun,
