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Lectron Carburetor Kits for 4-Cylinder Drag Bikes | High Performance Upgrade for Drag Racing (38mm-59mm)

Name: Lectron Carburetor Kits for 4-Cylinder Drag Bikes | High Performance Upgrade for Drag Racing (38mm-59mm)
Brand: Lectron Fuel Systems
SKU: 1900-L-4
Price: 1999.99 USD
Availability: InStock

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199999

For Riders Who Want

The 4-Cylinder Drag Bike Carburetor Kit includes four matched Legacy Series carburetors with cast aluminum bodies, standard metering rods, and power jets for high-RPM fuel control and adjustability. Designed for inline 4-cylinder engines, the kit comes with a 4-1 drag bike throttle cable, and custom intake manifolds — delivering consistent, synchronized performance with the adjustability needed to dominate on race day.

Includes

All kits come with:

(4) Legacy 38mm-48mm Carburetor and setup for vehicle
(1) 4-1 Throttle cable for required function (except 30mm)
(4) Custom Intake Manifolds
(2) Lectron Stickers
(1) Tuning Manual and Installation Guide

*NOTE: All carburetors come standard with billet float bows.

Built for speed. Tuned for the strip.
The 4-Cylinder Drag Bike Carburetor Kit is engineered for riders chasing peak horsepower and consistency in high-RPM, wide-open-throttle conditions. Designed for inline 4-cylinder engines and modern custom drag bike builds, this kit delivers explosive top-end power, sharp throttle response, and balanced fueling across all four cylinders.

Using precision-matched carbs from our Legacy Series, this system features cast aluminum construction, standard metering rods, and power jets — giving you the adjustability and reliability you need to push your machine to the limit. Each kit includes four synchronized carburetors, and a drag bike-specific 4-1 cable to ensure total control off the line and down the strip.

🏁 Who It’s For:
Drag racers running vintage or custom inline-four engines who want maximum power, repeatable launches, and the ability to fine-tune their fueling for track conditions.

Metering Rod

The Standard Metering Rod is a key component of our dual-circuit fueling system, engineered for smooth throttle response and clean power delivery. Positioned directly in the manifold pressure zone, it responds instantly to changes in throttle input, drawing fuel based on airflow velocity and engine load.

The rod’s contoured surface and precision grind control the fuel pickup signal with exceptional accuracy. As airflow increases, the rod delivers atomized fuel in a fine vapor—optimizing combustion, improving throttle snap, and eliminating flat spots.

Unlike traditional carburetors with overlapping circuits, the Standard Metering Rod delivers a linear fueling curvewithout hesitation or surge. This design enhances rideability, fuel economy, and power across the entire RPM range.

Power Jet System

Adds external adjustability of fuel for wide-open throttle positions. Fine tune your top end for increased power without sacrificing midrange - Ideal for racing and high-speed performance.

Proven Performance

Our carburetors are built on well-established fuel delivery principles that have been tested across countless on and off-road applications. Whether you're racing, trail riding, or running a custom build, you can count on predictable throttle response, smooth power delivery, awesome peak power, and long-term reliability.

This is performance you can feel — without needing to overthink it.

Cast Aluminum Construction

Our carburetors feature a precision-cast aluminum body, offering the ideal balance of strength, weight, and affordability. Cast aluminum provides excellent heat resistance and structural integrity, making it well-suited for off-road and high-vibration environments.

Unlike billet or plastic-bodied carbs, cast aluminum keeps costs lower while maintaining reliable performance where it counts. It’s a practical, proven material that delivers real-world durability without adding unnecessary expense.

No-Jetting

Our carburetors use a dynamic fuel delivery system that self-compensates for changing conditions like altitude, temperature, and humidity. Unlike traditional carbs that require constant jetting adjustments, ours deliver consistent fueling with no extra effort.

Just bolt it on and go — whether you’re riding at sea level or climbing elevation.

Carb Sizes: Which One is Right?

Go Big, Go Billet

48mm | 97mm Overall Length/52mm OD Spigot/60mm OD Bell
52-50mm | 114mm Overall Length/56.5mm OD Spigot/76mm OD Bell
52mm | 103mm Overall Length/61mm OD Spigot/76mm OD Bell
54mm | 103mm Overall Length/61mm OD Spigot/76mm OD Bell
56mm | 103mm Overall Length/61mm OD Spigot/76mm OD Bell
58mm+ | 103mm Overall Length/61mm OD Spigot/76mm OD Bell

The Legacy 48mm+ Series carburetors are precision-machined from billet aluminum and built for high-output race engines that demand serious fuel and airflow. Available in 48mm to 59mm bore sizes, these are purpose-built for drag racing, big-bore builds, and wide-open desert or dune machines. With massive internal volume and razor-sharp response, they’re made to feed engines that operate at the edge of performance.

All sizes in this range are constructed from billet material, ensuring durability, consistency, and smooth fuel delivery under extreme conditions.

Common OEM carbs replaced:

Lectron 48mm–50mm

Keihin PWK 41 / 44

Mikuni TM 48 / TMX 50

S&S-style or custom-modified large-bore race carbs

Other billet or modified 45mm–58mm single-carb setups

Example fitments:

Honda CR500 (drag build or dune setup)

KTM 500 / 550 2-stroke (carb conversion)

ATV: Banshee (big-bore single-carb conversion or twin-carb setup)

ATV: TRX250R with extreme stroker kits

Custom sand drag bikes and methanol-fueled hill shooters

Snowmobiles using large single-cylinder or twin-cylinder 2-stroke conversions

Legacy Custom

87mm - 120mm + Overall Length
35mm + Spigot OD
50mm + Bell OD

The Legacy Custom carburetor is built for riders, racers, and builders who need a solution that doesn’t exist off the shelf. Starting at 30mm bore size and up, this option is fully customized to your exact fitment, performance, and packaging needs. Whether you’re working around frame constraints, building a one-off engine, or pushing the limits in racing, the Legacy Custom gives you the freedom to spec it your way.

We offer complete flexibility in dimensions—most Legacy Custom builds start at 87mm+ overall length, 35mm+ spigot OD, and 50mm+ bell OD, but we can tailor nearly every aspect to your application.

Common OEM carbs replaced:

Anything from Keihin, Mikuni, Lectron, or other aftermarket carbs where standard sizes or shapes won’t fit

Custom billet or machined setups that no longer exist or can’t be sourced

Modified or adapted carbs that never quite worked right

Example fitments:

One-off engine swaps (custom kart, ATV, or bike builds)

Custom twin or triple-cylinder single-carb conversions

Big bore drag bikes with extreme port timing and airflow needs

Vintage or exotic engines where OEM parts are unavailable

Intake-limited setups with frame or shock clearance issues

Tell us what you need—we’ll build it.

Lectron Legacy (30mm - 44mm)

30mm | 93mm Overall Length/37mm OD Spigot/62mm OD Bell
34mm | 93mm Overall Length/40mm OD Spigot/62mm OD Bell
36mm - 44mm | 88mm Overall Length/46mm OD Spigot/62mm OD Bell

The Legacy Series carburetors (30mm - 44mm) are designed to replace OEM carbs in the 30mm–44mm range. These sizes are ideal for small to mid-displacement engines running performance upgrades or big bore kits. Expect smoother fueling, better throttle response, high power and a hassle-free, no jetting experience compared to outdated stock carbs.

Common OEM carbs replaced:

Keihin PWK 30

Keihin PJ 34

Mikuni TM 30

Mikuni VM 30

Mikuni TMX 30–36

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FAQ

+ What's the difference between Lectron carbs and stock/OEM carbs?

Lectron carbs are built for riders who want simplicity without compromising performance.

Unlike stock carbs that rely on jets and constant tuning, Lectron uses a metering rod system that automatically adjusts fuel delivery based the conditions around you (elevation, temperature, humidity, etc..) . No jets to swap. No guessing. Just ride.

Here’s what sets us apart:

No Jetting Required – Adapts to changes in altitude, temperature, and mods automatically.
Smooth, Predictable Power – Strong bottom-end and midrange torque with linear throttle response.
Fewer Parts, Less Tuning – Simpler design means less time wrenching and more time riding.
Built for Performance – Whether you're racing or trail riding, you get better performance without the hassle.

It’s the performance you want, with the simplicity you’ve been missing.

+ What if I need help with install or tuning?

No problem - we've got you covered. Our dedicated support team has extensive experience tuning and installing Lectron carburetors across a wide range of bikes and riding styles. Whether you're working through your initial setup or fine-tuning for specific conditions, we're here to help. Reach out anytime - we'll make sure your carb is dialed in and your bike runs like it should.

+ Will the carb come pre-tuned?

We have over 50 years of experience with tuning carburetors. We setup each carb to a fundamentally determined setting based on information you provide to us. Your carb will be very close or spot on when received. With that said, varying factors like the bikes condition, wear, maintenance, oil ratio, and age of fuel can have an effect with tuning. We suggest a simple, slight tuning at install to achieve max performance and preferability. Once you set it, forget it. Enjoy no-hassle.

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