Does the switch have a BATT / MAG selector on the key? If it does its wired for a battery. That will aid in starting as youll at least be able to hear the coils sizzle. If no battery simply make some jumpers to a battery on the running board with the + to the feed wire on the coilbox and a ground. If you do that, its no problem, BUT, dont turn the key on and backfeed battery jolts into the magneto. In laymans terms, that can discharge the magnets.
So now you need to provide some details: what year is it? No starter; ever? or was it removed and blanked off? Is there a generator? If so you will need a battery or when it runs the generator will go critical and overheat.
If it hasnt run for a long time consider towing it slowly around the block in high gear with the plugs out. Oil everything up really good. If you luck out and turn the key to MAG while doing this you may just hear the individual coils sizzling. Leave the plugs attached to the wires to discharge the coils as they fire so they dont burn internally. DO NOT TOW BY THE FRONT AXLE!!! Tow from the frame only! ws