Suzuki Carburetor Troubleshootingby Michael Perlman
Carburetor issues are one of the most common and vexing aspects of owning a motorcycle. All those tiny jets, needles and ports seem daunting from the outside. But once you bury your fingers in a float bowl or two, troubleshooting the carburetor on your Suzuki will become second nature, saving you hundreds of dollars over going to the dealership for service.
Gas Tank Inspection
So you're getting flat spots in midrange, choppy throttle response and an occasional stall at low idle? Before you tear into the carbs, look at the gas tank and work your way inside. Make sure all the tubes are properly connected to the petcock. Is the fuel line fastened properly? How about the air breather tube and vacuum line to the carbs? Check your gas cap to see if it's ventilating properly. If not, the tank could be vacuuming fuel upward instead of pushing it to the carbs. Check the petcock filter to see if there is any debris kicking around inside, impeding the flow of fuel.
Fuel Line Inspection
Disconnect the fuel line from the tank, and use a catch pan to collect the fuel that inevitably spritzes out. Point the tube downward to drain out the rest of the fuel. Now disconnect the fuel line from the carbs, and inspect it. See any debris or corrosion? If not, then it's time to delve into the carburetors.
Removing the Carbs
Before removing the carbs, you must take a few steps. Drain the float bowls by holding the catch pan underneath the carbs and loosening the float bowl drain screws at the bottom of each bowl. Once all fuel is drained, set aside the catch pan and loosen the clamps holding the carbs onto the cylinder head. If you have enough room, it is possible to work on your carbs without removing the throttle cables by swinging them to one side of the bike and draping a towel over the engine. If you don't have enough room, disconnect the throttle cables, emission tubes and any other parts connecting them to the bike. When you finally remove the carbs, they should come off as a unit braced together with air breather hoses sticking out. If you run individual pod air filters, remove them before taking off the carbs.
A Good Cleaning
By this time, it's obvious that there's something wrong with the carbs, and they most likely need a cleaning and adjusting. Find out exactly where your bike's main jets and pilots are, unscrew them, and soak them in carb cleaner. Remove the float bowls and check for sludge. Clean the float bowls with carb cleaner as well. You can use compressed air to blow corrosion out of the tiny holes in the carburetor components, but make sure you have a firm grip on them. Clean any part of the carb body that appears corroded or blocked. Let the carburetor parts dry, reinstall them and reattach the carbs to the bike. Connect all cables and fasten all clamps.
Floats, Needles and Other Settings
Check out the floats in the float bowl. If the floats are out of sync, use a caliper to measure the distances on each carb. Make sure that they are all to spec via the bike's service manual. Also, see if the needles are on the right clip and setting using the service manual. If your needles or floats are off, it could lead to irregular fuel flow and an unhappy bike. While you're at it, make sure your main jets and pilot jets are to spec. This is especially important after buying a new bike. If your carbs are geared for an aftermarket exhaust, ensure that their settings are compatible with the exhaust manufacturer.
Carb Sync and Routine Maintenance
After three to four hours of carb troubleshooting, your bike should be running like a champ. If it's still a little ornery, the last step you can do is a carb sync. You'll need a carb sync tool and an external fuel line to do this, so make friends with that mechanic down the street. Once you balance the carbs, your bike should run like new. Always troubleshoot from the outside in, and service the carbs on schedule.
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