PRO SERIES Carburetor Kit for ATV's & Quads | Peak Performance & Ultimate Simplicity (38mm-40mm)

For Riders Who Want

Designed specifically for high-performance ATV and quad applications, the PRO SERIES Carburetor Kit delivers instant throttle response, strong low-end torque, and clean top-end power in a no-jetting, easy-to-install package. Machined from billet aluminum and paired with a chrome-plated brass slide, it’s built to withstand harsh off-road conditions while delivering smooth, predictable throttle control.

Equipped with a three-circuit fuel system — the Xcelerator Metering Rod, power jet, and torque jet — the PRO SERIES provides precise fuel delivery across the entire RPM range without requiring manual jet changes. Each kit includes an ATV-specific throttle cable (single or dual) for necessary function, and 4-Strokes include Custom Intake Manifold making this a complete performance upgrade for both single- and dual-cylinder.

Includes

Kit Includes

  • (1) Black Anodized PRO-SERIES ATV Carburetor Setup for Vehicle
  • (1) ATV Throttle Cable (dual or single)
  • (1) Custom Intake Manifold (4-Stroke Only)
  • (2) Lectron stickers
  • (1) PRO-SERIES Tuning Guide


Xcelerator Metering Rod

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.

Torque Jet Technology + Power Jet System

Torque Jet Technology + Power Jet System

The PRO-SERIES combines our newly designed Torque Jet Technology in addition to the Power Jet System. Designed to deliver power exactly where you need it — the bottom-end grunt and wide-open throttle performance is unrivaled. The torque jet design activates at low throttle openings to improve off-idle response and drive out of corners, while the power jet kicks in at higher RPMs to maintain strong top-end fueling without bog or drop-off.

Together, these two circuits and the Xcelerator Metering Rod create an incredibly responsive throttle at all RPM and put real power to the ground without hesitation. Whether you're trail riding, racing MX, or pushing through deep sand, the PRO-SERIES is designed for performance, and delivers.

Internal Fuel Circuits

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.

Chrome Plated Brass 'H' Slide

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.

Redirect Slide Ramp

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.

Carb Sizes: Which One is Right?

Short Body / New Style

Short Body / New Style

  • 78mm Overall Length
  • 46mm OD Spigot (Engine Side)
  • 62mm OD Bell (Airbox Side)

The BILLETRON and PRO-SERIES Short-Body carbs are designed to replace modern OEM carburetors in the 36mm–40mm range. With a more compact overall length, they’re a direct fit for newer bikes and ATVs where space is tighter—especially behind the shock. These carbs deliver massive gains in throttle response, torque, and top-end without sacrificing fitment.

Common OEM carbs replaced:

  • Keihin PWK 36
  • Keihin PWK 38
  • Mikuni TMX 36
  • Mikuni TMX 38
  • Other 36–40mm short-body OEM carbs

Example fitments:

  • 2021 YZ 250
  • 2017 KTM 300 XC
Long Body / Old Style

Long Body / Old Style

  • 90mm Overall Length
  • 46mm OD Spigot (Engine Side)
  • 62mm OD Bell (Airbox Side)

The BILLETRON and PRO-SERIES Long Body carbs feature a 90mm overall length and are designed for older bikes that originally came with longer carburetors. With a 46mm spigot outer diameter, they fit most aftermarket reed cages and select OEM intake manifolds. These carbs are ideal for riders upgrading from older 34mm–38mm carbs and looking for modern performance in a compatible form factor.

Common OEM carbs replaced:

  • Keihin PWK 38 Air Striker (Standard Body)
  • Mikuni TMX 38 (Early Models)
  • Keihin PJ 36/38
  • Mikuni VM 36/38
  • Other OEM carbs from the 90s and early 2000s with similar dimensions

Common fitments:

  • Older 2-stroke bikes from the 1990s to early 2000s
  • Vintage builds and restorations using aftermarket reed cages

Modular Fitment:The adapter extension is removable, allowing the carb to convert fromLong Body (90mm)toShort Body (78mm)if needed. This makes it ideal for riders who want fitment flexibility without buying another carb.

Note:
Many OEM intake manifolds on bikes 20+ years old require a 43mm spigot outer diameter. For those applications, the Long Body - V version is recommended for proper fit without modifying the intake boot.

If you're upgrading from a vintage 36–40mm carb and need a longer overall length for proper throttle cable alignment and manifold fitment, the Long Body is your go-to.


Customer Reviews

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Robert C.
I would have to say that it is one of the best performance bolt on's that I have purchased in a l...

Recently purchased the Lectron Billetron PRO-Series carburetor and I would have to say that it is one of the best performance bolt ons that I have purchased in a long time. From the tuning right out of the box to the way it makes my motor about pull my arms out of there sockets when Im getting on the gas, hands down the best carb on the market I would purchase all over again before any other brand of carb.