I have two 185 bayou's (the 4 wheeler version, one is a part's unit that is still pretty complete) and had the same problems getting the one I have running now back going. (no power to the head light either on mine) Just haven't had the time to sort though the wiring. I haven't had the two side by side but think engine, trans and rear end is the same on the trike and 4 wheeler. ( I am use to only honda's trikes) The muffler on mine I had a plate welded up so I could just re-mount it. Going to cut a hole in it and counter sink some kind of muffler into the rear of it one day to tone the noise down. Found a new china carb on ebay as well around 25 bucks.
185s - 200 top, cam, k&n air filter, clutch pack with hd springs, ft fork extenders ( had since the early 80's)
185s - k&n air filter, clutch pack with hd springs, ft for extenders(been in the family since new was my uncles)
250 big red - winch, narrow ft tire kit (dads)(bought new)
200x - Roller, going auto-x, with white fenders.
110 late make square headlight
Blaster roller getting a spare 185s engine.