Classic Motorcycle Build

Bendix Carb For V-Twin Harley

Originally fitted to sixties Harley-Davidson Big-Twins and Sportsters, the Bendix carb is a popular choice for classic motorcycle builders and restorers who still ride their old scoots. They are relatively simple units that easy to mount and easy to tune. The three styles made for Harley V-twins are a 38mm fixed main jet, 38mm adjustable main jet, and 40mm adjustable main jet.

Bendix carb rebuild

Bendix Carb with Adjustable Main Jet

An updated version of the Bendix carb with adjustable main jets is currently sold under the name Zenith-Bendix. These are not necessarily better, but they do offer more tuning options. Properly set up, they will provide good performance and gas mileage.

Bendix HD Carburetors

Big-Twin Harleys came equipped from the factory with 38mm Bendix carbs from 1971 through 1975. In 1974, the FL Touring models switched to Keihin, while the FX models continued using the Bendix. From 1972 through early 1976, Sportsters were fitted with the 38mm Bendix. The larger, 80 cubic-inch BT motors may work better with the 40mm units.

Bendix Carb Rebuild

The Bendix HD 16P12 unit seen in this article is from my old 1976 XLH Sportster. It is the fixed main jet style. Like the other models, it has a dual venturi and uses an accelerator pump.

tools and supplies

Shop Tools and Supplies at Zoro

Carburetor removal and disassembly is straightforward. It is held to the intake manifold with two bolts. The throttle-body is held on by the main jet tube assembly at the bottom of the carb. A 9/16" socket removes it.

After completely disassembling, check all parts. If the float is gas-soaked, replace it with a new one.

Bendix Carburetor for Harley

Clean the Carburetor

Consider investing in a gallon can of Berryman's Chem-Dip (about $25) and soak the body and float bowl (not the float). This stuff will dissolve the old dried-up remnants of fuel and remove any sludge. Be careful - Chem-Dip will eat plastics, puff up gaskets, remove paint, and other nasty things.

Bendix HD Carb Rebuild

To get a good cleaning without soaking the carb in Chem-Dip, spray down into the fuel wells enough to make it puddle, then let it sit overnight. After soaking, rinse the carb parts with water and blow dry. A little brushing from a nylon brush will help clean up nice.

Bendix carb rebuild instructions

Around the top of the brass fuel tube assembly there is a fiber washer and an O-ring. The O-ring will rot away over time and will allow fuel to leak into the intake manifold. There should be a new one in the rebuild kit (buy a quality kit). Harley still sells the USA Zenith part under number 27762-71TA.

Bendix Carburetor for Harley Sportster

After blowing out all fuel circuits and air passages with compressed air, reassemble the carburetor. Allow parts to sit (preferably overnight) to ensure all parts are dry. Remember to install the new throttle shaft seal.

Bendix Carburetor for Harley

If you have an original Harley Bendix carb, you may want to re-use the old steel needle, as the newer ones are Viton-coated, which may have issues with some of today's gasoline alternatives.

Bendix Carburetor for Harley

Bendix Carb Float

Turn the carb body upside down and install the new bowl gasket. Float clearance is measured from the end of the float to the gasket, and should be 3/16". An easy way to measure this is with a 3/16" drill bit.

Bendix Carburetor Rebuild
Bendix Carburetor for Harley

Once the carb is rebuilt and back on your bike, screw the main jet needle (closest to the air cleaner) inward until the spring is almost but not quite coil-bound (the original spring is about 5/8" long). Then turn the needle four full turns out. Next, set the low speed needle (closest to the engine) one full turn open from the closed position. After starting the engine, some minor adjustments may be needed to "dial it in".

Bendix Carburetor for Harley

Bendix Carb Rebuild Tips

motorcycle carb rebuild

Being a compact unit, the Bendix sits "tucked in" and allows you to run almost any type of air filter. Round chrome is a popular choice. The one in the picture is an old Gary Bang unit.

read Carburetor Troubleshooting

read Kick-Starting An Old Motorcycle