OK I picked up another gl1200. It sat for 15 years. I knew that going in and my one prerequisite was the motor had to turn over which it does. So now I've got the carb rack off and on the bench. After tearing one carb apart to see what kind of shape it's in I find everything is froze. I think the carbs are toast. So I'm considering doing the single carb conversion. It doesn't look all that difficult. But my one question is do I block off the secondary air supply system?