top of page

The BIlletron "Big Air" 39mm Carburetor from Lectron Fuel Systems - made just for big bore two stroke engines


It's here. The Lectron Big Air 39mm carburetor!


Learn more about the all-new Big Air carbureter here in our YZ500 Build & Giveaway YouTube video! 


-All the great lecton features you've grown to love, packed into one do-all carb for big bores

-No jetting, ever!

-No need to worry about temperatute or elevation changes


The New Billetron Big Air boasts several new features, including:


-Billet construction

-Metric hardware

-OEM throttle cable compatibility for most two stroke applications.

-Shorter overall length and height

-New metering rod adjustment mechanism (1/8th turn increments)

-Bowl drain with integrated g-force kit-

-H-Style slide (aluminum now vs. Zinc previously)

-New top cover design with two screws and locating tabs

-Gasketed body halves with dowel pins vs. sealant

-New bore and bell design

-New choke design

-New float system

-New high flow, sprung needle seat valve

-New bowl material (clear, more impact resistant)

-Horizontal power jet screw that is adjustable by hand

-Relocation of carburetor vents with 4 lines


Performance Improvements

-Significantly more bottom end hit

-Significantly improved throttle response

-Faster power jet activation

-New slide design and metering rod location improves idle

-Finer idle adjustment (much finer threads on screw)




The BILLETRON™ Big-Air has been designed for big-bore two strokes delivering unparalleled peak performance. The BILLETRON™ Big-Air bore dynamics have been specifically engineered to maximize mass air flow and velocity in mid to wide open throttle positions. This allows substantial gains in top end performance while controlling air velocity from low to mid throttle positions that generate a substantial off the throttle response and massive top end power.


The BILLETRON™ Big-Air design is aimed at taking advantage of the existing bottom end vacuum of big bore two strokes while maximizing the mid - top end air flow capabilities. Continuing in the success of previous designs, BILLETRON™ Big-Air is manufactured with a 39mm venturi diameter that incorporates a tested degree of taper that increases air velocity. The result is a controlled and directed air velocity in low throttle positions and substantial gains in mass air flow in the mid-top end positions. Engineered to deliver a responsive & controlled bottom end while changing the game in top end performance. 


  • 300cc-500cc Applications
  • Unparalleled top end performance - Peak horsepower gains up to 15%
  • Externally adjustable power jet - make quick on the track fuel adjustments to mid-top end fuel delivery
  • Fuel delivery adjustability for both the bottom end and top end allow for fine tuning with future performance modifications and/or riders response preference 
  • Improved bottom end throttle response and rideability 
  • Increased fuel economy of 30%
  • ISO Certified precision machining paired with billet aluminum construction for unbeatable product consistency and performance
  • Drop Jetting – Allow the technology to mechanically compensate for air property changes
  • Adjustable power jet – easy, on the track tuning, for mid to wide open fuel delivery. Adapt to the technicality, and rider preference, of each track without sacrificing performance across all throttle positions
  • Improved Idle - Centralized and focused air flow to the fuel signal creating improved idle consistency


  • 30 Day Guarantee: Buy it & rip it - If you don’t love it, contact our support team within 30 days of purchase and get your money back 
  • 1-Year Product Warranty 
  • Available Technical Support throughout the Lectron journey. Let us help you get the most out of your machine! 


Easy Tuning Kit: This includes quick change billet thumbscrews for the top cover and a metering rod adjustment tool.


Special Anodizing: Alter the color of your Billetron Big Air. Color options include black, red, blue or orange (raw silver is cool too)

Lectron Billetron Big Air 39mm - for Big Bore Two Strokes 300cc-500cc