Lights

[Bird150]

JUst finlshed a rebuild of my lambretta 150s but I am having a problem with the lights,when I put the headlights on the running bulb 12v will blow and headlights will not work why thoughts.Tony

[Meds]

There could be a lot of reasons for this to happen.
First, cleaning up all of the connections, including the ones on the headlamp holder make sure they are all in the right place.
Make sure you have good earths, from all of the lights and from the frame to the engine.