Sorry about the delay...had something going on here. My suggestion would be to try the jets that come with the carb and see how it performs. If you have issues then consider re-jetting. Weber has jetting kits that contain all sorts of parts to play with the mixture. I decided to just replace the main and secondary jets first before going any further. I bought the individual jets from some other place...they're cheap.

The main thing you need to remember is the idle screw cannot be turned in more than 1-1/2 turns. If it is it will throw off everything. If you follow Weber's tuning tips closely you should be OK. If you Google Weber carb tuning you'll find a lot of good info. These carbs are very popular in Europe.

One drawback that I've found is you'll lose your dashpot which kicks up your idle when the air conditioner compressor kicks on and if your idle is low it may run rough, especially with the lights on.

Try to keep your idle at or below 900rpms as it may want to run-on when you shut down. If it still does richen up your mixture a little bit (turn the mixture screw out an eighth of a turn at a time and then test drive). I keep a small screwdriver handy and am still putzing with the settings, but it's never run better.

Also get your ignition systems as good as it can be before the swap, along with any possible vacuum leaks. You'll get rid of a whole box full of vacuum lines, just make sure all of the lines from the vacuum manifold are plugged tightly.

And, after pulling off the whole works I noticed that the coolant hole under the carb (your Mikuni has coolant circulating through it) was leaking into the manifold. Use a high temp RTV sealant around the bottom and top of the carb to manifold gasket at the coolant hole. I also used a large flat file and worked the flat surfaces of the adapters before reassembling. So far so good. It starts instantly at below zero (f).

One last thing. The fast idle screw was set way too high from the factory. Make note of its location in case you want to turn the fast idle down, it can be a little hard to reach after the carb is installed. Let us know how it goes.