Main Jet, 140 for D-Series Carb, Sold Each

OVERVIEW

Precision fuel delivery is the backbone of any high-performing air-cooled engine, and the EMPI 140 Main Jet for D-Series carburetors is a critical component for achieving that perfect stoichiometric balance. When you''re tuning your Weber DGV, DFEV, or EMPI EPC series carburetor, the main jet takes over the heavy lifting once you transition out of the idle circuit and into the mid-to-high RPM range. A 140 main jet provides a specific orifice diameter designed to meter fuel precisely, ensuring your engine doesn''t stumble from a lean condition or bog down from being overly rich. For the dedicated VW enthusiast, having a selection of high-quality brass jets is the only way to account for variables like displacement increases, camshaft profiles, and exhaust scavenging characteristics. This jet is manufactured to exacting tolerances, ensuring that when you install a 140, you are getting exactly the flow rate required for your specific calibration needs.

At Appletree Automotive, we understand that "close enough" isn''t good enough when it comes to your vintage Volkswagen''s fuel system. Whether you are running a progressive 2-barrel setup on a daily driver Beetle or a twin-carb configuration on a rugged off-road rail, the main jet is what dictates your power curve under load. The D-Series main jet is specifically engineered to fit the most popular progressive and synchronous carburetors used in the air-cooled world. By swapping to a 140 jet, you can fine-tune your air-fuel ratio to maximize horsepower and protect your cylinder heads from the excessive heat generated by lean-running conditions. These jets are sold individually, allowing you to mix and match sizes to find the "sweet spot" for your engine''s unique breathing requirements, altitude, and local fuel blends. Don''t settle for generic components when you can utilize genuine EMPI precision to keep your flat-four humming perfectly across the entire powerband.

FITMENT

This 140 Main Jet is designed for use with D-Series carburetors, commonly found in the following applications and kits:

• EMPI EPC 32/36F Progressive Carburetor Kits.
• Weber 32/36 DGV, DGAV, and DGEV Series Carburetors.
• Weber 38 DGAS and DGMS Synchronous Carburetors.
• Weber DFV, DFEV, and DFAV Series Carburetors.
• VW Type 1 Beetle & Karmann Ghia: 1954 through 1977 (with upgraded D-Series carburetors).
• VW Type 2 Bus, Transporter & Kombi: 1955 through 1971 (with upgraded D-Series carburetors).
• VW Type 3 Squareback, Fastback & Notchback: 1961 through 1973 (with upgraded D-Series carburetors).
• VW Thing (Type 181): 1973 through 1974.
• Custom Dune Buggies, Sand Rails, and Baja Bugs utilizing Weber-style progressive induction systems.

SPECS

The following technical specifications ensure compatibility with your air-cooled fuel system tuning project:

• Jet Size: 140 (Equivalent to a 1.40mm precision-drilled orifice).
• Material: High-grade 360 Machined Brass for corrosion resistance and thermal stability.
• Series: D-Series (Compatible with EMPI and Weber-style progressive bodies).
• Thread Pitch: Precision-cut to standard D-Series carburetor specifications.
• Head Style: Slotted for easy installation and removal with a standard flat-head screwdriver.
• Stamping: Clearly marked with size "140" for easy identification in your jet box.
• Sold As: Individually (Sold Each).
• Manufacturer: EMPI.
• Part Number: 44-1056-0.

PRO TIPS

1. The Golden Rule of Jet Cleaning

Never, under any circumstances, use a metal wire, needle, or drill bit to clean a brass main jet. Brass is a relatively soft metal, and even the slightest scratch or abrasion inside the orifice will permanently alter the fuel flow characteristics. If your 140 jet is clogged with old fuel varnish or debris, soak it in a high-quality carburetor cleaning solvent and then use high-pressure compressed air to blow it out. If the blockage persists, it is always safer and more accurate to replace the jet entirely rather than risking an inconsistent fuel mixture that could lead to engine damage.

2. Tuning for Altitude and Temperature

Remember that jetting is not a "set it and forget it" process if you live in an area with extreme seasonal changes or high elevation. A 140 main jet might be perfect for a 1600cc engine at sea level, but if you take that same Volkswagen up into the mountains, the thinner air will cause the engine to run rich. Conversely, in freezing winter temperatures, the air is denser, which can lean out your mixture. Always keep a "jet kit" with sizes slightly above and below 140 so you can adjust your D-Series carb to maintain peak performance and fuel economy regardless of where the road takes you.

3. Reading Your Plugs for Perfection

To verify if the 140 main jet is the correct size for your engine, perform a "Plug Chop." Drive the vehicle until it reaches operating temperature, then find a safe, open stretch of road where you can run the engine at wide-open throttle (WOT) through third or fourth gear. While still at WOT, quickly turn off the ignition and coast to a stop. Pull your spark plugs and inspect the porcelain insulator. A light tan or "coffee with cream" color indicates your 140 jet is likely spot-on. If the porcelain is white or blistered, you are too lean and need a larger jet; if it is sooty and black, you are too rich and should consider stepping down a size.