PRO-4 32mm Carb Kit | Ultimate Throttle Response, Precision Fuel Control, Peak Power (32mm)

PRO-4 32mm Carb Kit | Ultimate Throttle Response, Precision Fuel Control, Peak Power (32mm)

$899.99
$899.99
Shipping calculated at checkout.

Engineered specifically for the CRF150R and other small-bore 4-strokes, the PRO-SERIES 4-Stroke Kit transforms your bike’s throttle response and power delivery. Designed to eliminate jetting hassles, it delivers a smooth, torque-rich powerband that adapts automatically to changes in elevation and conditions.

— AVAILABLE FOR PRE-ORDER NOW! Expected to ship mid-November.—

Its billet aluminum construction provides exceptional strength while the chrome-plated brass slide ensures long-term durability and precise metering. Combined with the Idle Fuel Circuit, the PRO-SERIES kit gives your CRF150R crisp throttle response, consistent performance, and a broader, more controllable power curve — so you can focus on riding, not tuning.

Kit Options

Lectron PRO-4 32mm carb kit is designed for 4-stroke motors and is a high performance upgrade for the OEM FCR 32/33.

Includes

Kit includes the following:

  • (1) Black Anodized PRO-4 32mm Carburetor
  • (1) Domino Throttle Assembly
  • (1) Throttle Cable
  • (2) Lectron Stickers
  • (1) PRO-SERIES Tuning Guide
Description Features + Compatability Chart Specs FAQ

More Power. More Pull. No Jetting.

The Lectron PRO-SERIES 32mm carburetor is the ultimate fix for riders tired of bogging, hesitation, and endless jetting problems. Built on our proven PRO-SERIES platform, it delivers stronger acceleration, cleaner fueling, and consistent performance - without jets to clog or tune.

Featuring a 32mm high-velocity bore and our new Xcelerator™ metering rod, this carburetor delivers a burst of fuel the instant you hit the throttle. The result? Zero bogs, zero hesitation, and explosive acceleration that transforms how the bike rides.

The Torque Jet has been relocated to the engine side of the carburetor, functioning as an external idle screw for quick, precise idle adjustments - no tools required. Combined with an integrated Power Jet and Lectron’s adaptive fueling system, your bike runs stronger and smoother in every condition.

Each kit includes everything needed for an effortless installation - carburetor, throttle cable, and throttle assembly - so you can spend more time riding and less time wrenching.

🏁 Who It's For:

For riders seeking consistent, reliable fueling performance on small-bore 4-stroke engines. This setup eliminates common issues such as off-idle bogging, inconsistent jetting sensitivity, and delayed throttle response. Optimized for 4-stroke platforms like the Honda CRF150R - it delivers stable air/fuel control across a wide range of operating conditions for smoother, more predictable power delivery

Xcelerator Metering Rod

Provides a burst of fuel enrichment when ‘whacking’ the throttle for instant throttle response in all RPM’s. This innovation is a leap in metering rod technology by sustaining the hassle-free, no jetting benefits, while leveling up performance and throttle response. No compromise, just power made easy.

IFC: Idle Fuel Control

Unlike sealed-off idle circuits or carbs that require disassembly to make changes, our externally adjustable Idle Fuel Control gives you direct access to fine-tune low-RPM fuel delivery on the fly. Need to bump idle up after a cam swap or richen things for cold starts? A simple turn of the screw does it.

This isn’t a “set-it-and-pray” system — it’s precision control where it matters most.

Don’t settle for a carb that idles how it wants. Dial it in. Get control.

Chrome Plated Brass 'H' Slide

Throttle feel starts at the slide — and this one’s built to deliver. The chrome-plated brass ‘H’ slide adds durable mass for a more stable, weighted response, while the chrome finish drastically reduces friction to prevent sticking or galling under heat.

The result? A buttery-smooth throttle pull that stays consistent, even in the harshest conditions.

Don’t settle for flimsy or grabby. Feel the difference. Ride smoother.

Internal Fuel Circuits

Fully optimized internal fuel circuit routing, meaning the power jet and torque jet systems are fed through machined passages inside the carburetor body — not external hoses. These fuel passages have been designed to expedite fuel delivery by reducing the required vacuum necessary to pull fuel through each circuit and also shortens the fuel travel path which allows for near immediate fuel delivery. The result, a noticeably quicker throttle response and immediate power transfer to the ground.

By eliminating external fuel hoses, the PRO-SERIES not only looks cleaner but is also easier to install and less prone to hose-related damage in harsh riding conditions.

SafeDrain Overflow Bowl

SafeDrain is Lectron’s integrated overflow control system engineered to protect your engine from the complications of fuel overflow in the most demanding conditions. Whether you're navigating steep climbs, hammering through vibration-heavy terrain, or transporting a hot bike after a ride, SafeDrain gives excess fuel a clean exit path and enhanced geometry for improved sealing.

By combining overflow redirection with added venting for incline and decline situations, SafeDrain Bowl ensures stable fuel pressure and consistent performance where other systems fail. It’s peace of mind built into the bowl — no tuning, no fuss, just protection you can trust.

Full Install Kit Included

Every carburetor kit comes with the required functional components, including a matched throttle cable and basic hardware, to adapt the carburetor for use on most stock setups. While not guaranteed to be a direct bolt-on for every model, these parts are necessary to ensure the carb operates correctly once installed.

This kit is designed to replace OEM controls to ensure proper function — saving you time sourcing the right cable or adapter parts. Fitment may vary depending on your bike or ATV’s specific setup, and additional modifications may be required.

Redirect Slide Ramp

Designed exclusively for our PRO-SERIES & BILLETRON carburetors, this unique slide design does more than control throttle - it redirects airflow to sharpen the fuel signal, delivering quicker, cleaner throttle response and more consistent power delivery across the rev range.

Billet Aluminum Construction

Our carburetors are CNC-machined from billet aluminum, delivering superior strength, precision, and durability. Billet aluminum starts with a solid block of aerospace-grade aluminum, each body is machined to exact tolerances, ensuring flawless accuracy and consistent quality that cast construction simply can’t match. Unlike cast carbs, billet aluminum provides enhanced reliability, long-term durability, and a premium finish that reflects its performance-driven design.

Built for riders who demand the very best, our billet carburetors combine long-term reliability with championship-level performance. This is more than just a carburetor—it’s a premium upgrade that reflects the highest standard of engineering and design.

… …

FAQ

What type of fuel is recommended for 4-Strokes?

We recommend using premium fuel with a minimum octane rating of 91 for all 4-stroke applications. Lower-quality or low-octane fuel can cause tuning issues, poor performance, and starting problems—not just with our carburetors, but with any carb system. For the best results, stick with fresh, high-quality fuel to ensure consistent combustion and optimal throttle response.

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.

Why Choose Lectron?

Lectron Fuel Systems has been pushing the limits of performance fuel systems since 1974 with the introduction of the first metering rod carburetor. We have a long and varied history in motorsport, supplying fuel systems for Drag Racing, Motocross, Enduro, Snowmobiles, Karting, Road Race, and many more. We bring a vast knowledge of how to make things go fast and combine it with a commitment to constant improvement. Our products are tested extensively on both the dyno and in the real world, by riders of all disciplines and skill levels, to ensure performance, durability, and reliability. All of our products are manufactured and assembled in the USA, and we pride ourselves on passionately providing expert technical support to back up our products.

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.