There are 3 main sources of noise- intake roar, exhaust and primary gears. Do a search here, I think the solutions are covered well. You make a inner cover on the clutch cover to dampen sound there, maybe an added muffler onto the one you have and you make a snorkel/ sound box for the intake.
I bought a basket case moped for the paperwork, put the headlight on my bike from it, added stop and tail light and licensed it as said moped. Oh yeah, I stamped the numbers on the frame. Problem solved.
The engine is covered because I like to pedal slowly on the sidewalk at times (no problem where I live) and the engine is very quiet.
Where is K town?