I have found no joy in getting and aftermarket unit. They all seem to be backwards with the fuss in the way. I'm looking to get a cheap one and use its parts to fix mine
I have thought about doing this but I would simply measure the outlet.
Then again online sellers will say they have something that fits so you would assume ok.
As long as there isn't any friction modifiers then it is fine. Most motorcycle oils don't have these anyway. I have found semi synthetic allows the engine to rev a little easier
My aftermarket exhaust im sure was fitted to the bike in the USA before it came here. The collars are very similar to the oem but not quite although do work. Hopefully you discover the issue
Have considered using them myself as I have never heard a bad report and I like the setup. Although I'm one of those that likes something to be as it was made kind of people
High probability of a stuck needle. Tapping the side of the bowl will usually knock out free. A set of new ones would be a good idea. Does the $500 rebuild include a set of carbs