The bazaar result of drilling a jet far larger to surprisingly get the engine to run better perplexed me. So I researched the 1100 carbs and I think I found the explanation. The 1100 has a power valve that is partially a metering rod. Mikes Carburetor made this video to describe how it works. See this;https://www.youtube.com/watch?v=i2eWyUbCtJU. With the power valve stuck closed (that often happens on 1100s) the engine doesn't get the extra fuel it needs when under a load. When working correctly, the power valve functions as a second jet. I recommend cleaning the power valve and replacing the jet with one not drilled. With no power valve and an over size jet, the carb delivers an overly rich mixture the engine can't use when cruising.