HomeTechnical ReviewsFBG Lectron Downdraft Carburetors

FBG Lectron Downdraft Carburetors

FBG Lectron Downdraft Carburetors
…explained by Paul Gast

Late model bikes typically have downdraft fuel injected intakes. Drag bikes, for the most part, use FBG Lectron Carburetors. Up until now, to install Lectrons on lets say a Hayabusa, curved rubbers or FBG aluminum manifolds were required. These manifolds work fine and are trouble free. However, the extra length of the intake tract has a negative effect on high rpms and high rpm hp. Kevin Gilham at Lectron Fuel Systems designed a new DD float system. Now you could mount the carbs directly to the port with a simple, pro stock style straight rubber manifold. I liked it. The new float and pick up design does not fit in a standard Lectron float bowl. Lectron designed a new aluminum, large capacity bowl that has many positive functions:

1. Accommodates the new float and pickup system.
2. Increases fuel capacity.
3. Keeps the fuel more stable at the pickup point.
4. Adds weight to the carb which diminishes fuel shaking or foaming at the pickup.

I borrowed Bill Pippards Busa T/G bike for the Dyno test. I knew we would see top end improvement, but not sure how much. First run was made with the bike and last years carbs exactly as it was raced in 2009. The result was a dead on overlay of previous dyno pulls. Next, we installed the new Lectron Downdraft Carburetors. With the same jets as Bills old carbs, the engine ran lean. This is good. It wants more fuel. I got lucky on the jet call and nailed it on the next pass. Talk about easy to tune! I’d like to keep bragging about my awesome tuning ability, but I suppose you want results.

+ 5 Peak HP
+ 8 Ave HP
+ 23 HP @ high rpm

Check out the run on Youtube: http://www.youtube.com/watch?v=0fHH0OHAoy0.
Remember, these results are compared to the same size 44mm Powerjet Lectrons used in side draft fashion with angled boots.

We typically see these results compared to other carbs or fuel injection, but compared to the same size Trons, we were VERY PLEASED! I’ve been on the Lectron wagon for 35 years and continue to be amazed.


Why do I need these Downdraft Lectron Carburetors?
1. Horsepower.
2. Definitely cool carbs.
3. If you have DD intake port.

If I already have Lectrons, can they be made into downdrafts?
NO. Downdrafts are very custom.

Do I need Powerjets?
YES. This is how you adjust the mixture at full throttle.

Gravity feed or fuel pump?
Downdraft carbs are set up for gravity feed. We highly recommend gravity but low pressure pump is possible.

Are my curved manifolds OK?
Sure. If you are happy with your performance level.

Can I use Billet Bowls on my standard Lectrons on my GS or KZ?

Why would I?
1. More capacity.
2. You like cool stuff

How much money?
FBG Lectron Downdraft carb set includes cables, Quick throttle, grips, fuel line, and manifolds. $1,995.00.
Add $400 for large billet induction bells. Available in 38mm, 40mm, 44mm.
Add $400 for 48mm.
Set of 4 Billet Bowls alone are $399.00

Where do I get these Carburetors?
Downdraft Lectrons or Billet Bowl kits are available exclusively through Fast By Gast and the FBG Distribution network.

Definitely a very good new product.

Thank you for your time.
Paul Gast

**Bill Vose runs a 6.66 with the new FBG Lectron Downdrafts!!**

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