How to Rebuild a Carburetor for Vehiclesby Contributing WriterUpdated June 12, 2017
If your Vehicles is not running the way it should, it might be time to rebuild the carburetor. S & S is a popular carburetor Vehicles a Vehicles V-twin engine. The fuel to run the Vehicles runs through the carburetor, mixing with the right amount of air, leaving sediment and particles behind gumming up the inner works of the carburetor. Once the particles are in the carburetor, the bike will not perform as it should. It will run sluggish and possibly not even start. A rebuild kit Vehicles the carburetor can be purchased Vehicles most motorcycle part supply stores. The process of rebuilding a carburetor is not too difficult.
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Disconnect the fuel line and drain the carburetor. Remove the carburetor from the intake manifold. Check the plugs that are located in the body of the carburetor for signs of leaking. If signs show that they are leaking, replace the plugs.
Remove the idle mixture screw. Count the turns it takes to remove the screw, make a note of how many turns it took. Check the throttle plate for wear. There should be no light showing when the carburetor is closed. Replace if necessary.
Clean the idle mixture screw and mark it with a marker just to the tapered part. Replace the screw by screwing it completely into the carburetor. Remove the screw and check to see if any of the marker has been rubbed off. If it has, use the new idle mixture screw from the kit and discard the old one.
Remove the enrichment plunger nut and spring from the carburetor. Check the tip of the plunger for wear.
Take the screws out of the bowl of the carburetor. Do not remove the cap.
Remove the float pin screw. Locate and remove the float pin, float and needle. Replace if warn with new parts in the rebuild kit.
Take the seat from the bottom of the carburetor bowl. Install the new seat that is in the rebuild kit.
Check the ejector nozzle for kinks or wear. Install the new nozzle O-ring.
Clean and check the float for holes. Install a new needle. Place the entire unit back into the bowl. Move all the parts to be sure they move easily.
Turn the bowl over and take out the screws that held the cap in place. Take the balls and O-rings out of the casting.
Replace the ball checks, seats, spring and diaphragm with the new ones supplied in the rebuild kit.
Replace the pump shaft and boot. Install the new bowl gasket and secure with the provided screws.
Reinstall the cables before bolting the carburetor back onto the intake manifold.
Position the carburetor with the backing plate and breather assembly and bolt back together.
Replace the idle screw, turning the same number of turns it took to take it out. Start the bike and check the cables. Adjust the idle screw if necessary for the proper idle. Take her for a test ride to ensure all is running smooth.
Items you will need
Carburetor rebuild kit
Remove the front seat from the motorcycle. Turn the fuel petcock to the off position. Loosen the hose clamp that holds the fuel line and disconnect it from the carburetors. Remove the rear hold-down bolt and lift the fuel tank off the motorcycle. Set it aside on a stable surface and cover the paint so it will not be damaged.
Remove the top of the air box and the air filter. Remove the four bolts that hold the air box in place. Loosen the clamps that hold the intake air boots to the carburetors. Ease the boots off the carburetors, lift the air box free, and set it aside.
Disconnect both of the accelerator cables from the carburetor linkage. Loosen the clamps that hold the carburetors in the intake boots. Gently work the carburetors out of the boots and lift them free of the motorcycle. Move them to a clean, well-lit work bench in a well-ventilated area. Never separate the carburetors. Reassembly requires special tools and calibrations of the accelerator return springs that are done at the factory.
Remove the float bowls from each of the carburetors, using a Philips screwdriver. Carefully remove the jets from each carburetor with a flat-head screwdriver. Take care not to mix up the parts: keep the parts with the original carburetor they came from.
Inspect and clean all of the jets thoroughly. Soak them in carburetor cleaner if necessary. Use a magnifying glass to make sure you can see light clearly through the hole in each jet. Ensure that all of the main jets are the same size and all the pilot jets are the same size. Replace any jets that cannot be cleaned with new ones of the same size.
Remove the floats and float needles from each carburetor. Inspect the rubber tip of each needle for wear. The tip should be an even triangle with no lip worn around the edge. Replace all needles that show signs of wear. Again, do not mix parts. Ensure that the floats that came out of each carburetor return to that carburetor.
Place the jets back in the carburetors. Do not over-tighten them; the threads are brass and will strip. Place the floats and needles back in place. Check float height with a float height gauge, ensuring that the height in all four carburetors is the same.
Reinstall the float bowls with new gaskets provided in the carburetor rebuild kits. Do not over-tighten the screws that hold the bowls in place.
Turn the carburetors over and remove the plastic top covers. Remove the springs and slide the diaphragms out of the top of the carburetors. Turn them over and let the carb needles fall out. Washers may fall out with the needles: take care not to lose these washers.
Clean the needles thoroughly with carburetor cleaner. If a needle shows signs of wear, replace it. Inspect the diaphragms for leaks by holding them up to a strong light and attempting to look through them. Even the tiniest hole will cause the diaphragm not to function properly. If you detect any holes, replace the faulty diaphragm.
Reinstall the diaphragms and needles and ensure that each needle has an equal number of washers on it. Reinstall the springs and plastic caps after inspecting them for damage, using new O-rings provided in the carburetor kits.
Reinstall the carburetors on the motorcycle, ensuring that the clamps on the intake boots are tight. Reinstall the accelerator cables.
Using a remote fuel source and carburetor synchronization tools, synchronize the carburetors so each is pulling the same amount of vacuum, both at idle and at ¼ throttle. If you are unfamiliar with this process or do not have the tools, reassemble the motorcycle and take it to a local shop.
Assembly is the reverse of disassembly. Reinstall the air box, the fuel tank and the seat, ensuring that all fasteners are tight.
Items you will need
Basic hand tools
Motorcycle repair manual
Float height gauge
Carburetor rebuild kit
Carburetor synchronization tool
Set the carburetor on a cookie sheet. Remove all the screws and linkages for the accelerator pump, choke, dashpot or power valve assemblies. Retain any springs or clips.
Remove the screws for the air horn. Lift up the air horn. Disconnect any remaining choke linkages. Flip the air horn over and remove the float pin and float. Remove the fuel inlet seat.
Remove all distribution plates and venturis from the main body. Watch for presence and placement of check balls in the venturi plate and the accelerator pump passages. Remove the main jets in the bottom of the main body.
Coat the choke plate, main and secondary plate screws with penetrating oil and let them set for several hours. Coat for the second time with penetrating oil. Carefully remove the plate screws. These screws are small and will break off commonly. If one breaks off, file off the stub from both sides to remove the shaft. Remove any nuts, pins or clips retaining the plate shafts. Remove the shafts and any accompanying springs. Remove the idle screws and tension springs. Remove any remaining parts.
Cleaning and detailing
Place small parts in a basket and into the carburetor cleaner. Put all the larger parts into the carburetor cleaner. Let soak for at least one hour. Remove and drain. Wash all parts with Simple Green cleaner and water. Immediately dry with compressed air and a blower nozzle. Make sure to blow out all passageways.
Chase each screw hole threads with an appropriate size tap. Make sure to do the plate shafts. If a shaft screw broke off in disassembly, center-punch the screw and drill out the body on a drill press with the appropriate bit and re-tap the hole with the correct tap. Blow all the passages clear with compressed air.
Hang the parts to be painted on hooks. Paint all the main parts with Carb Renew. Paint all the linkages with cad paint or underhood black. Allow the paint to fully cure.
Install the plate shafts and accompanying springs, pins, nuts or clips. Install the choke, main and secondary plates on their respective shafts. Replace screws that were broken with new ones. Install the idle screws and tension springs, tighten to lightly seat, then back out 1-1/2 turns.
Place check balls back in the correct passages. Install the main jets in the bottom of the main body. Install the fuel inlet seat in the air horn. Install the float and pin. Following the float adjustment directions for the specific carburetor, adjust the float height to specification by bending the tab.
Install all distribution plates and venturis with appropriate gaskets. Install the air horn with a new gasket. Route all linkages through the holes. Replace all screws and tighten.
Install the accelerator pump, spring and new gasket. Install the choke assembly with a gasket. Replace linkages in correct holes. Install the power valve and new gasket. Install dashpots and brackets. Install any remaining shields.
Make sure all parts have been replaced. Perform any other bench adjustments outlined in the specific carburetor directions. Install the carburetor on the car.
Items you will need
Appropriate carburetor kit
Assorted slotted screw drivers
Assorted Phillips screw drivers
Carburetor cleaner with basket
SAE tap & die set
Simple Green cleaner
Machinist's flat file
Complete machinists's drill set
Bench grinder with wire wheel
Replacement screws as necessary
Eastwood's Carb Renew
Eastwood Cad paint
Eastwood's Underhood black paint