Shortly after completing No Starving Patriots, you’ll get a message from Boozer, informing you about Bike engines he heard. Leave the Bunker and simply climb the Radio tower. Once you reach the top, look at the O’Leary Safehouse using your Binoculars to see the smoke emanating near the safehouse. Loot the items nearby then climb down to complete the mission.
We have questions and answers related to this topic which may also help you: