The short version
Inside the carb, there are different jets that control different throttle position. So if you want to richen up a specific throttle range (for example 1/4 to 1/2 throttle) then you will change that jetting system. But it isnt really cut and dry becuase there is overlap. meaning that multiple jets are working at the same time. See the following chart for what jets control specific throttle positions.
Well, the main jet (the 152.5) only controlls 3/4 to full throttle, meaning that by swapping it out, you are only going to notice a difference on the highway because that is really the only time you are at full throttle. For driving around town, you are usually between 1/4 and 3/4 throttle. So to richen up that part of the carb, you have remove or shorten the factory governing spacer that is on the needle jet in your carb. It was put there by Suzuki so that you carb will run on the lean side (not ideal). It has been determined that if you file the spacer down to half its orignial size then your carb will perform much better at idle to 3/4 throttle. This is what it looks like
To get to the spacer, remove the top of the carb (4 phillips head screws and they are in there real tight), then remove the diaphragm slide from the carburetor and look down inside it. Two small screws hold a metal plate over the slide needle. Removing the plate, you'll see the small, white plastic spacer with a hole through it sitting on top of the needle. take it out (take care not to lose the spring) and using a file, file it down to 1/2 its original size, then reinstall it. A spring under the needle clip will now push the needle up to the plate occupying the space vacated by the white spacer. The distance that the needle has been 'lifted' is the thickness of the discarded spacer - and that's ideal. With the needle raised, more fuel will flow by it, meeting the actual needs of midrange running.
*I Thank everyone on this board that helped me with this mod, and who took the time to take the pictures*
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