The stage 2 is probably the most popular way of increasing power. It includes the needles from the stage 1 kit, larger front and rear main jets, larger front and rear pilot jets (some kits do not include the pilot jets), and K&N drop in filters. The drop in filters are a direct replacement to the stock air filter and are placed into the stock air box. The Stage 3 includes K&N clamp on filters and precise tuned jetting. The clamp on filters are "clamped" directly onto the carburetor and the stock air boxes are entirely removed, improving air flow. Your setup depends on; your exhaust pipes, elevation, air filters and other factors. Careful consideration must be taken before deciding on which jets to use for your setup. A call to Factory pro www.factorypro.com or Dynojet, www.dynojet.com can help determine what setup you need.

Needles (from the stage 1 kit) -  They are used in conjunction with the main jet, as the throttle increases
the needle rises inside the carburetor throat, allowing more fuel in.
Main Jets - They are used to monitor fuel during full throttle operation
Pilot Jets - Used to monitor fuel during idle or just above idle.
Fuel Mixture Screw (aka idle air mixture screw, one screw for each carb) - Allows the tweaking of the fuel mixture
during idle, and must be done with a stage 1, 2 or 3 setup. Most people do 2.5 turns out. From the factory, the screw is
blocked by a brass plug. The plug can be removed by drilling a hole in the plug, inserting a screw into the plug, gripping the screw with a pliers or a similar tool and pulling the plug out. Be cautious when drilling: once the brass plug is drilled through, the mixture screw is right behind the plug and can be damaged by the drill bit. This is done for both carburetors.

Click here for the Stage 2 Instillation Guide

Here is a picture of the main jets, here I have a 127.5 and a 137.5
This site shows the jet choices available http://www.sudco.com/mikunijets.html
scroll down to:
Front and rear main jets - N100.604 Large Round

Here is the front and rear carb pilot jets. I forget what size they are lol.
This site shows the jet choices available http://www.sudco.com/mikunijets.html
scroll down to:
Front carb pilot - VM28/486
Rear carb pilot -  N151.067 (OEM)


Here is a picture of the Clamp on K&N filter part # - RU-1820