You should get the 6 Volt tail light bulb, thats what is supposed to be there. Your blinkers wont continuously blink if you just have the key on. The engine should be running and charging the battery. You will notice as your driving the blinkers will work just fine. I have 3 NC50s a 78, 80 and 81. I had to bring them all back from the dead, and all of them had wiring issues I had to deal with. They all work perfectly now after many head scratching nights. I will also reccommend the replaceable headlight bulb option a previous poster mentioned, well worth it. ALL the bulbs should be in and working so you dont blow the bulbs one by one. I have a very cheap alternative for the little instument bulbs too if you need them, just let me know. Oh yea, I got the 6 volt 1157s from NAPA. ? Go figure.