How to install a new jet kit with my new pipes
You can change the jets in your Keihen carb without removing the carb. First remove the air cleaner cover, air filter element, and the backing plate. There are four screws holding the float bowl onto your carb, turn the petcock to the off positon (if it has an off positon) and remove the four screws and drop the float bowl down.
You will be able to see them main jet very easily. It's screwed into the main jet holder and extends down to the very bottom of the float bowl when the bowl is on the carb. Simply screw the old jet out and screw the new one in.
The slow jet will not be visible directly. It's up inside a hole just to the rear of the main jet holder. You may need a mirror to find it. Once you've found it, use a narrow bladed screwdriver to remove the old one and install the new one. Replace the fuel bowl, air cleaner assembly. Check for proper operation of the throttle before starting the engine.
Now, if you jet kit contains a different slide needle, you'll have to remove the carb to replace this. Once you get the air filter assembly off the carb, loosen the throttle cables at the throttle grip and disconnect them at the carb. Then disconnect the fuel line and the vacuum line from the carb. Pull the carb out of the intake manifold.
To replace the needle, remove the four screws that hold the top cover on the carb. One screw is longer than the rest, remember where it goes. Carefully remove the cover. There is a large low tension spring under the cover and a rubber diaphragm. You do not have to remove the slide to change the needle but it's a lot easier if you do. Lift the diaphragm out of the groove around the top of the carb. Carefully. lift the slide out of the carb. Down inside the slide, you'll see a plastic needle retainer. Take this out and lift the needle out of the slide. Install the new needle as instructed with your jet kit. Reassemble in reverse order being very careful to insure the diaphragm is properly seated in it's groove around the top of the carb. If not, you will puncture the diaphragm and then have to replace it. It ain't cheap either, Sometimes you have to use just a bit of grease to get the diaphragm to stay in the groove.
While you've got it down this far, you need remove the anti-tamper plug that covers the idle mixture adjustment screw in the event it hasn't been removed previously. Turn the carb upside down and locate a round plug just on the engine side of the float bowl. It is about 1/4" in diameter. Using a small drill bit, carefully drill though this plug. It isn't thick and you just want to drill through the plug, If you put too much pressure on the drill, you will damage the screw beneath it. Just barely drill through the plug. With the plug drilled, insert a small self tapping sheet metal screw. Use a pair of pliers to work the plug out of it's hole. Now, you'll see the idle adjuster screw. Carefully turn it inwards until it seats while counting the turns. Once the adjuster barely seats, turn it back out three complete turns. This is your starting point.
Reinstall the carb with a new carb to manifold seal. Check for the proper throttle operation before starting the engine. Start the engine and allow it to warm up a bit. Adjust the idle mixture screw for smoothest idle and the throttle stop screw so that the engine idle speed is about 1000-1200 RPM.
Good Luck