why are you running 38mm carb with the stock boot ?
I suggest you put bigger main jet until you found witch one will net let the engine rev.  act like a rev limiter
if I am you I will start with 350  mj
also, you must ride the bike to test the main jet and the needle position.
your engine must be hot

a engine that is lean is smoking a lot when cold ....

you should have 2 adjustment on the carburetor one is the idle air and the other is the slide height ( idle speed )