The Suzuki Bandit is a four-cylinder, carburetted motorcycle, designated in the GSF series. It comes in a 600cc or 1200cc configuration. Adjustment of the carburettors is necessary when changing intake, exhaust, or modifying for better performance. Emission regulations in your area affect what carburettor adjustments you may legally make to your motorcycle. Carburettor adjustments require the same procedure, but may differ slightly from model to model. Consult your manual before beginning any project.
Remove the seat. Remove the rear hold-down bolt for the fuel tank. Enable access to the carburettors by lifting the tank off the motorcycle and setting it aside. Place the tank in a well-protected area, where it will not be scratched, dropped, or damaged.
Remove the carburettor assembly. Loosen the clamps on both the air box and engine intake boots. Disconnect the accelerator cables. Disconnect the wiring to the throttle position sensor, on the number four carburettor, and move the assembly to a clean and dry bench.
Turn the assembly over and remove the screws holding the float bowls in place. Set the float bowls aside. Check the jet sizes currently installed. When rejetting, decrease the idle jet size slightly, when you increase the size of the main jet. Use the information provided with the intake and exhaust kits, to determine what size jets to replace the stock ones with.
After installing the new jets, turn the carburettors back over, and remove the upper caps. Replace the o-rings, within the caps, located on the 1200cc Bandit. Inside, a diaphragm is attached to a slide. Flip the diaphragm upside down, carefully, to release a needle. Within your carb kit, are shims for this needle that look like very small washers. These shims should be labelled, with sizes ranging from 0.5 to 1.8 mm (0.02 to 0.07 inches). Shim the needle, to the size specified by your kit recommendation. Replace the slide and diaphragm to their original positions, and install the cap, using a new o-ring, if required.
Turn the carb over and find the idle adjustment screw. Using a flat head screwdriver, turn the screw in all the way, until it gently rests against the carb body. Turn it back out, a half turn at a time, to the specification provided in your kit, usually from 1.5 to 2.5 turns.
Install the carburettors on the bike, and tighten the clamps that hold them in place. Attach the accelerator cables and the throttle position, sensor wiring. Turn the accelerator a few times, to ensure proper and smooth routing of the cables, during operation. If there is any question of routing, consult the diagram, found in your manual.
Install the fuel tank, and start the motorcycle. Allow the bike to idle, and rev the engine, checking for smooth operation. Take the motorcycle out on the road for a test ride, and keep close track of your fuel mileage. This will let you know if your adjustments were successful, and if your bike is running properly.
Things you need
- Hand tools
- Carburettor kits
- Carburettor jets