On the 250, there is a hard vacuum line that goes to the electric choke on the YFA carb. Where does it originate on the manifold? I just replaced the YFA on my '75 and when I moved the line gently so it would clear the carb, it snapped off at the manifold due to corrosion. I can't find where it originated to save my life. The replacement carb doesn't require the vacuum line so I want to seal the hole at the manifold but finding the origin spot has me perplexed. Anyone??