SmartCarb Flat Slides-Understanding their Genealogy, Blog #3

Posted by Scot Wilson on


I hear very often, “Those SmartCarbs by Technology Elevated look a lot like a Lectron and aren’t they the same thing?” The lineage is very much the same, however, the SmartCarb is technologically a 50 year newer evolution of the initial design. The purpose of this blog post is to discuss the differences half a century of development brings between the SmartCarb and the Lectron.

A steady progression of the art has evolved through the on-going work of the late inventor of the design, along with a large number of researchers at General Motors Corporate, GM Lectron Division, Edelbrock Corporation and Technology Elevated. Variants of the design have been around for over 45 years, some of which have made inroads into the aftermarket with reasonable success.

As discussed previously, the SmartCarb is the only “True” single circuit system that utilizes an internally vented and pressurized float bowl with a precision flat ground metering rod. No additional circuitry, such as a pilot system, nozzle jet, or main jet is ever needed. In contrast, Lectron uses multiple circuits that include multi-angle metering rods and the addition of a power jet. "These combined overlapping processes create unequal fuel distribution and wet heavy fuel droplets and are not as efficient as the SmartCarb’s single circuit which delivers all of the fuel in precise mixtures and a fine vapor state".

On my Mt Lemmon road tests, one significant benefit of the SmartCarb is that there was no drop in power or need to adjust the carbs at different altitudes as the carbs provide ambient air density compensation for altitude, temperature and humidity. “Less air, less fuel, more air, more fuel with little to no variance in A/F ratios.” Therefore, our 1981 Ducati 900 ss MHR ran clean and maintained superior performance throughout our tests!!

The key to the success of the SmartCarbs is the internal venting and with the pressurized float bowl that produces these significant performance and fuel economy benefits. There are no external overflow hoses to “bleed” pressure from the float bowl. Lectron vents to the atmosphere via overflow hoses like conventional carbs and as a result cannot fully compensate for air density changes. As a result, the Lectron must be constantly adjusted, like other carburetors, for large changes in ambient air density conditions. Internal venting and float bowl pressurization allows the SmartCarb to provide proper top end fueling without the need for a power jet like the Lectron.


Due to these advanced design features of the SmartCarb, in addition to performance superiority, the SC also provides additionally more fuel economy than the Lectron. Superior fuel economy is accomplished because of the very fine vapor atomization and that there is no fuel lost via overflow hoses or through the heavy wet spray of raw fuel from a power jet. This results in much better fuel economy due to efficiency and no losses of raw fuel to the environment. “Patented check-valves within the float bowl pressurization vents keep fuel in the float bowl whether there is float needle failure (flooding) or if the bike finds itself on its side.” There is an indirect safety benefit for racers who need not be concerned if they were to have that “off” while racing and the concerns fuel pouring onto to their bike’s hot engine and exhaust from the carbs.

Another SmartCarb advantage comes from a proprietary and patented venturi shape. As the venturi is not round, it is shaped to most efficiently focus signal directly at the metering rod thus dramatically improving atomization. I can attest to a very linear power delivery and smooth, seamless throttle action. The Lectron by contrast has a conventional round, smooth bore.

A logistical difference is that we have been able to make basic Ducati cables work with our SmartCarbs with a slight bit of filing needed on the cable connectors. The Lectron requires a different throttle cable and throttle handset for most bikes and at additional cost.

SmartCarbs are extremely easy to adjust and tuning can be done externally by hand and without specialty tools. My Blog Post #2 went into some detail on the tuning benefits of these SmartCarb Flat-Slides. The Lectron in contrast, requires removal of the top cap and using their special metering rod calibration tool to make adjustments and obviously comes at additional cost.

The real advantage that we found in tuning these SmartCarbs is the ease of making precise, linear adjustments in tuning settings that come from the availability of 10 clicks per revolution. In contrast, the Lectron has only 4 positions per revolution and a common complaint that I hear is that the user gets lost between choosing between non-optimal settings.


Another advantage that I have found with the design of the SmartCarb is that there is a float bowl drain which is standard on all models. It makes preparing for seasonal storage very easy. However, since I live in Arizona and can ride all year round, the real advantage of the float bowl drain can be used as a diagnostic tool to measure float bowl fuel levels. (see below) This was extremely helpful when dealing with getting the float adjusted correctly on the front cylinder of our Bevel Drive Ducati where the carb is angled on the manifold. Being able to see the fuel level was a real benefit in determining proper fuel height.

Lectron uses a clear float bowl which has a “cool factor” as well as seeing float level. However, they are prone to leaking much like the set of clear float bowls that I purchased for my 40 mm DelOrto’s. As I replaced the clear float bowls on the DelOrto’s so does Lectron offer a billet bowl that eliminates the potentially leaky float bowl but for an additional $95.

As it relates to pricing, SmartCarbs come in a 38 mm Cast model for $474 fully equipped as of this writing. CNC Billet SmartCarb models are available in 36, 38, and 40 mm for $599. In the middle is the Lectron which is $500 "plus" based upon your needs. However, the best reason to purchase a SmartCarb is the proven technological advances that it has over all other carbs: 10-14% in horsepower gains, 30% better fuel economy, automatic altitude correction, external adjustability and up to 80% reduction in hydrocarbon emissions.

Come and experience the pinnacle of carburetor technology at Italian Iron Classics, LLC. Stay tuned as we fire-up our 1000 cc Ducati Monster S2R in our TT 1000 chassis!! As the next generation of SmartCarbs is soon to be released, it will be in time for "firing up" our TT 1 Racer for the Street. 


As always, if you have specific questions or if you would like to learn more about this exciting new technology and the organizations that have performed the tests on which the data is based, do contact me at:

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