Modern Buddy

Hey all, so I've been trying to adjust my air/fuel mixture because I think my 2014 Buddy 50 is running lean. The issue is that it looks covered up with one of those brass caps. I've used a power drill to bore about 1/8 inch into it and it seems to just keep going. Does anyone know the depth of the welch plug on a 2014 Buddy 50 or have experience in this operation that could offer some advice? I included the most recent pictures, thanks!

I might be wrong but I've never heard of a hidden screw being blocked by a welch on a Buddy 50. I know on later year Yamaha Zuma scooters they have a hidden screw under a welch plug, that you barely drill into and loosen with a pick. I've removed several of them on Zumas. I recently tossed a non-salvageable, extremely corroded Buddy 50 carb in the recycle bin or I would have checked the carcass to see if this was true. Someone else with more Buddy 50 knowledge should chime in.

My 2013 has a black welch plug and researching how to drill it out