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BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)

Lectron Billetron Mini carburetor for 85cc two stroke dirt bikes
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
Lectron Billetron Mini carburetor for 85cc two stroke dirt bikes
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
BILLETRON Carburetor for 2-Stroke | Quick, Responsive, & Simple (25mm-29mm, 38mm-40mm)
64900

For Riders Who Want

The BILLETRON delivers smooth, predictable power through a billet-machined body and simplified dual-circuit fuel system. Designed for riders who want real performance without constant tuning, it features our proprietary Xcelerator metering rod and high-flow power jet. It’s refined, reliable, and built for the ride—not the toolbox. Performance made simple.

Description Features + Compatability Chart Specs FAQ
Includes

Each kit comes with the following;

  • (1) BILLETRON Carburetor and setup for your vehicle
  • (2) Lectron Stickers
  • (1) Tuning and Installation Guide

Bolt-on performance without the hassle.
The BILLETRON 2-Stroke carburetor is designed for riders who want consistent, smooth power with minimal tuning. Whether you're building up an 85cc or running a 300cc, the BILLETRON delivers excellent throttle response, reliable performance in changing conditions, and a simplified setup that just works — ride after ride.

Available in 25mm and 29mm for smaller-bore engines and 38mm and 40mm for full-size two-strokes, each size is optimized to match your engine’s displacement and powerband.

🏁 Who It's For:

Riders who want no-hassle performance, smooth throttle control, and strong gains over stock — from 65cc two-strokes to full-size trail and MX bikes. Ideal for anyone looking rideability and reliability without frequent tuning. Common applications include; KTM 65 SX, 85 SX, 125cc, 150cc, 250cc, 300cc, Yamaha YZ 65, YZ 85, YZ 125, YZ 250, Honda CR 85, CR 125, CR 250, Kawasaki KX 65, KX 85, KX 125, KX 250 and many more!

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.

Power Jet System

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.

Tailored Bore Design

Tailored Bore Design

Unlike one-size-fits-most OEM carbs, our bore is precision-tailored to match your engine's air volume for sharper throttle response and better power delivery.

It's like a well fitted suit vs one from your dad's closet - mass applied sizing doesn't cut it.

Avoid the pitfalls of generic carbs. Get fitted.

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.

SafeDrain Overflow Bowl

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.

Carb Sizes: Which One is Right?

BILLETRON MINI 29mm

  • 83mm Overall Length
  • 35mm OD Spigot (engine side)
  • 50mm OD Bell (Airbox side)

The BILLETRON MINI 29mm is built for 85cc–112cc 2-stroke engines and offers a direct performance upgrade over most 28–30mm OEM carburetors. With smoother power delivery, improved fuel efficiency, and no jetting required, it’s a favorite for riders who want a “set it and forget it” carb that delivers race-ready performance.

Common OEM carbs replaced:

  • Keihin PWK 26
  • Keihin PWK 28
  • Mikuni TM 26
  • Mikuni TM 28
  • Other 28mm–30mm stock carbs

BILLETRON MICRO 25mm

  • 82mm Overall Length
  • 31mm OD Spigot (engine side)
  • 44mm OD Bell (Airbox side)

The BILLETRON MICRO 25mm is designed for 65cc–80cc 2-stroke engines and serves as a direct upgrade over stock carburetors. It delivers smoother throttle response, improved fuel efficiency, and easier setup—perfect for riders who want better performance without the constant tuning.

Common OEM carbs replaced:

  • Keihin PWK 24
  • Keihin PWK 26
  • Mikuni TM 24
  • Mikuni TM 26
  • Other mini race bikes running 24–26mm OEM carbs
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.

Long Body - V

  • 90mm Overall Length
  • 43mm OD Spigot (Engine Side)
  • 62mm OD Bell (Airbox Side)

The BILLETRON and PRO-SERIES Long Body - V are built specifically for older 2-stroke bikes that require a 43mm spigot outer diameter to fit OEM intake manifolds. With a 90mm overall length and permanent adapter, this version is a direct replacement for many vintage setups—no boot stretching or manifold modification required.

Common OEM carbs replaced:

  • Keihin PWK 36/38 (Early models)
  • Keihin PJ 36/38
  • Mikuni TMX 36/38
  • Mikuni VM 36/38
  • Other OEM carbs from the 80s, 90s, and early 2000s with 43mm spigot fitment

Common fitments:

  • 1990s–early 2000s 2-stroke bikes using OEM intake manifolds
  • Vintage builds and restorations where OEM fitment is critical

Key Fitment Notes:

  • Features a fixed 43mm OD spigot for seamless installation with OEM intake boots
  • Adapter is non-removable, ensuring proper length and consistent fit
  • Maintains the same 90mm overall length as the standard Long Body version for throttle cable alignment and vintage geometry

If your bike was originally equipped with a 36–38mm carb and uses a 43mm OEM intake boot, the Long Body - V is the most accurate and hassle-free upgrade available. Built for legacy fitment—no compromises.

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FAQ

+ Will the BILLETRON work with my OEM Cable?

Yes. The BILLETRON products will

+ 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's the difference between the PRO-SERIES, BILLETRON, and H-SERIES?

Each series is designed for different rider needs and budgets:

  • PRO-SERIES: Our top-tier carburetor. Fully billet-machined with features like the Torque Jet, Power Jet, Xcelerator metering rod, internal fuel routing and a bore matched to your engine size. Built for serious riders who want maximum performance and tuning flexibility.
  • BILLETRON: Still billet-machined, but simplified for the rider who isn't looking to tinker with fine tuning. It uses just the Power Jet and Xcelerator rod for a more linear, predictable power-band but still provides excellent acceleration. Great for riders who want performance without constant tuning.
  • H-Series: Cast aluminum and fixed at 38mm, this is our value option. Simple to install, easy to tune, and ideal for riders who want better top-end power without breaking the bank.

All three perform great — it comes down to how much adjustability and performance you want, and how much you're riding.

+ 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.

+ 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.

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Customer Reviews

Based on 26 reviews
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C
C.H.

Excellent

E
Elias
Well worth it!!

After rebuilding my son's built Kx85, I noticed that the carb was dragging. Even after rebuilding it, still dragged a little. I learned about Lectron and how the carbs don't have jetting. Ordered one and wow!! It brought this bike to life! The throttle is snappier, idle is excellent and the powerband increase is awesome! My loves it and says it's a difference of night and day. Definitely recommend it. Thank you Lectron!!

G
Gabe
Consistent reliable fun

We bought our first Lectron in January of 2020 for my sons 65. Since then weve purchased 2 more and ran them on all of my sons 2ts - from 65,85,105 & now on to the 125. Weve logged tons of hours on our H and HV series Lectrons and as of recent, we also have a decent amount of time logged on the Billetron 38 installed on a KTM 125XC. Aside from being a super trick looking piece, the Billetron offers simplicity and takes the guess work out of having a clean and powerful running 2t at any temp or altitude. We were able to use our stock cable, and the thumbscrew option for the top cap is a worthy option making fine tuning even easier than before. The bikes run and sound great with the Lectrons installed. The fun factor of a responsive and crisp running 2-stroke is pretty hard to beat while the frustration of a bogging, oil sputtering, plug fouling, rough running bike can flat out ruin a great day of riding. As a father of 2 (both kids racing) along with 4 bikes to keep maintained and prepped, it has been a huge relief to not deal with jetting for the massive temp and altitude variances here in CO. Once the initial set-up and tuning is done, I can rely on our Lectrons to be pretty spot-on in just about every situation we encounter. Overall, weve been very happy with the product and would absolutely recommend it to anyone looking for consistent reliable performance for their 2-stroke machines.

F
Frank D
Great Performance Upgrade!

Performance with a punch in a small package ..is the best way I can describe it!Lectron has done an amazing job with the development of this series carb.We ride the Supermini class hare scrambles and the occasional MX using the same bike...and the difference is clearly noticeable!!We get better response and upper band power as well as increased horsepower and fuel economy.Its a silver bullet for anybody whos fought the factory carbs and all the adjustments for changing conditions...the time saved from changing out and testing the jets is now spent prepping for our race which makes the events considerably more enjoyable. The Lectron carb is really just plug and playits that simple.Id like to just say thank you to all the folks at Lectron.. your product has made our machines scream and have reliability that we never had before.Complete game changer!!

C
Chris
Big Air Review

I recently purchased the Big Air for a 1983 CR480R. I have used and been happy with the Billetron in a 250 so decided to pull the trigger on one for the 480. The Big Air came set up just a tad rich from the bottom to midrange, but only by a 1/4 of a turn. The 480 is notoriously a hard starter, but to my surprise it started up very easily with the new Big Air carb. The carb is smooth from the crack of the throttle all the way through the top end. I would highly recommend this carb for the big bore two stroke enthusiast out there. Basically plug and play, and the smoothness of the powerband is a great trait on these big bores.

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