Oil Leaking from Exhaust Studs Area

[kser]

Hey everyone, you've helped me raise my scooter from the dead once, so I would love some help again for this one.

Scooter:
GY6 150cc Motobravo Phantom GTX

Issue:
Oil leak around exhaust studs. not sure where originating from

When it started:
The exhaust pipe on my scooter rusted out and started getting holes. So I bought a new and put it on. Everything ran much better until I noticed some white/grey smoke coming from my muffler. I thought maybe it was the new exhaust pipe burning off something. It gradually started getting worse though and so I took it back off and saw (see pics in link below) that oil is coming from somewhere and leaking into my exhaust pipe.

I can't imagine how I would have messed something up by putting on the new exhaust pipe, but thought I'd mention it because the scoot had been running fine before this.

Scooter still runs fine as far as I can tell. Except that a bunch of smoke (i.e. burning oil?) comes out of my muffler

Help?:
I'm assuming some gasket somewhere has failed, but I'm not sure how to check which it might be without disassembling everything. Do I have to disassemble the scoot's top end? Or maybe someone has seen this before and can point me in an easier troubleshooting.

Pics: https://goo.gl/photos/jEBABkt38QsnGfnD8


Thanks so much!