Weber Carburetor Jet Size Chart & Drill Size Guide
This guide provides a practical reference for Weber carburetor jet sizes and drill sizes commonly used for cleaning, checking, and careful tuning work. Weber carburetors include many different models and jet types, so this guide should be used as a practical drill-size reference rather than a guaranteed manufacturer specification.
About Weber Carburetors
Weber carburetors are widely used in automotive, racing, vintage European car, VW, Porsche, kit car, and performance applications. Common Weber carburetor families include DGV, DGAV, DGEV, IDF, IDA, DCOE, ICT, and related models.
Depending on the Weber carburetor model, tuning may involve main jets, idle jets, air corrector jets, pump jets, emulsion tubes, and other calibrated components. Weber jet sizes are commonly identified using metric-style numbering, but the correct jetting depends on the carburetor model, engine, venturi size, elevation, and tuning goal. Always verify the specific jet type and application before cleaning, checking, or modifying a jet.
Which Drill Set Is Right for Weber Jet Work?
For Weber carburetor jet checking, cleaning, and careful sizing work, choose a drill set based on the jet type and diameter range you expect to work with.
Best Starting Point for Many Weber Jet Jobs: 20 Pc Selected Sizes Carburetor Jet Drill Set
Covers selected sizes from .0135" through .071", including many small metric and numbered drill sizes commonly used for carburetor jet cleaning, checking, and careful tuning.
Need More Continuous Numbered-Drill Coverage?
The 25 Pc #75–#51 Carburetor Jet Drill Set gives a broader numbered-drill range for general carburetor jet checking, cleaning, and careful tuning.
Want Backup Drills in Each Size?
The D7 50-piece #80–#56 set includes 25 sizes with two drills per size, useful when working with small, brittle carbide drills and smaller jet ranges.
Working on Larger Jets or Multiple Carburetor Brands?
If you work on larger carburetor jets, Holley-style ranges, Rochester/Quadrajet applications, Weber main jets, or several different carburetor brands, compare the full collection before ordering.
Important: carbide drills are brittle precision tools. Use light pressure, keep the drill straight, and avoid enlarging jets unintentionally during cleaning.
Weber Jet Size Chart & Drill Size Reference
Many Weber jet references use metric-style sizing, where a size such as 100 is commonly treated as approximately 1.00 mm for practical drill-size comparison. However, Weber jet numbering and actual fuel flow can vary by jet type, carburetor model, and manufacturer reference, so always verify the jet and application before modifying anything.
The Nearest Drill Size Reference column shows the closest practical drill size or drill range for comparison. It is meant for checking and reference only; always verify the actual jet and carburetor application before modifying anything.
| Jet Reference Size | Metric Reference | Approx. Inches | Nearest Drill Size Reference |
|---|---|---|---|
| 45 | 0.45 mm | 0.0177" | #77 range |
| 50 | 0.50 mm | 0.0197" | #76 |
| 55 | 0.55 mm | 0.0217" | #75 |
| 60 | 0.60 mm | 0.0236" | #73 |
| 65 | 0.65 mm | 0.0256" | #72 / #71 range |
| 70 | 0.70 mm | 0.0276" | #70 |
| 75 | 0.75 mm | 0.0295" | #69 |
| 80 | 0.80 mm | 0.0315" | 1/32" / #68 range |
| 90 | 0.90 mm | 0.0354" | #65 |
| 100 | 1.00 mm | 0.0394" | #61 |
| 110 | 1.10 mm | 0.0433" | #57 |
| 120 | 1.20 mm | 0.0472" | #56 / metric drill range |
| 130 | 1.30 mm | 0.0512" | #55 range |
| 140 | 1.40 mm | 0.0551" | #54 |
| 150 | 1.50 mm | 0.0591" | #53 |
| 160 | 1.60 mm | 0.0630" | 1.60 mm / #52 range |
| 170 | 1.70 mm | 0.0669" | #51 range |
| 180 | 1.80 mm | 0.0709" | 1.80 mm range |
| 200 | 2.00 mm | 0.0787" | 2.00 mm range |
Note: This chart is an approximate drill-size reference. It should not be treated as an official Weber specification or a guaranteed fuel-flow conversion.
Using Drill Sizes for Weber Carburetor Jet Work
Precision drill bits are commonly used in carburetor work for cleaning clogged jets, checking approximate jet size, comparing jet openings to known drill diameters, and carefully modifying jet orifices when tuning requires it.
Because drills come in fine size increments, they provide a practical way to work within small carburetor jet size ranges. When modifying jets, make small changes and verify results carefully. Weber jetting may involve several different jet types, so make sure you are working with the correct jet before using a drill.
Practical Drill Size Range for Weber Jets
Many Weber jet references fall within metric-style carburetor jet ranges. Smaller idle jets may fall into the range covered by selected-size and numbered drill sets, while larger main jets and air corrector jets may require larger metric drill sizes depending on the carburetor model and application.
For this reason, the 20-piece selected-size set may be a practical starting point for many smaller Weber jet checking and cleaning jobs, while larger Weber main jet or air corrector work may require comparing the full carburetor jet drill set collection before ordering.
Tips for Jet Sizing and Modification
- Use light pressure when working with carbide drills
- Keep the drill straight to avoid making the jet opening oblong
- Always verify size before modifying a jet
- Confirm whether you are working with a main jet, idle jet, air corrector jet, pump jet, or another calibrated component
- Make small, incremental changes when tuning
- Avoid enlarging jets unintentionally during cleaning
- When in doubt, replace the jet rather than over-drilling it
Conclusion
Understanding the relationship between Weber jet references and practical drill sizes can make carburetor cleaning, checking, and careful tuning more controlled. Use this chart as an approximate drill-size guide, verify the exact jet type and size before modifying anything, and choose the drill set that best matches the range of sizes you need.