Yamaha Viragos were manufactured from 1981 to 1996. This long production of cruising motorcycles saw several different engine, transmission, body and power variations throughout the years. One thing that did remain constant, however, is the need for regular maintenance and upkeep. If your motorcycle engine starts running poorly or refuses to start, this may be an indication it is time to clean that carb.
Take the seat off your Yamaha so you can access the fuel tank. Turn the fuel selector to "Off." Unscrew the bolt towards the rear of the tank, loosen the clamps and pull the fuel lines off. Pull the tank off the bike and put it to the side.
Loosen the manifold clamps near the air box and cylinders with a Phillips-head screwdriver. Also, disconnect the accelerator cable. Pull the carburettors out of these areas as a set.
Remove any rubber parts (such as diaphragms, O-rings and hoses) from your carburettor before you begin the cleaning process. The cleaners used for this may cause damage.
Clean the air and fuel passageways with spray cleaner, brush and compressed air. When you spray the cleaner into these parts, look for it to exit the other side of the passageway.
Unscrew the float bowls from the carbs with your Phillips-head screwdriver and put them to the side.
Use a flathead screwdriver to gently pry the jets out of each carb. Place a small cup full of carburettor cleaner next to each carburettor and place the appropriate jet in the cup next to the carb it came out of. Let these jets soak for at least an hour to remove any build-up. After that time, hold each jet up to a light to make sure you can see through it and it is not obstructed. If it is, use a metal guitar string or equivalent to clean the inside of these holes.
Spray carburettor cleaner on the carb bodies and wipe them down with a washcloth. Use cleaner and a toothbrush for tough areas. You can also use compressed air during this cleaning step if you want. Reinstall the jets into the carb body that it came out of once they are both cleaned.
Install new float bowl gaskets as you put the carburettor back into the Yamaha. Don't forget to put the rubber parts back on that you removed before you started cleaning.