Lectron Carbs

by Alan Buehner

Originally printed in issue #52 of Still….Keeping Track

Lectron Carburetors came out in the late 70's and were installed on the 1977 Penton 175 MC-5's with the size 36 mm carb. They were available as an aftermarket accessory in the Hi-Point catalogs starting in 1977 and were available for many different brands of bikes. They were available in 30, 32, 34, 36, 38, & 40 mm sizes. The size number is marked on the side of the carb.

Although the carbs were available in assorted sizes, the body of the carbs were all the same. The main difference is the the center bore which determines the size. The other difference would be the outside diameter of the intake bell (see photo of carbs A & B) and the the intake mount. These were milled down to fit the different brands of bikes. The Penton bikes use the Lectrons with the largest intake bell (see photo B).

Lectrons were available in 2 styles, the regular and the Power Jet.
The Power Jet has a nozzle inserted down into the intake bell of the carb which has a fuel line connecting it to the bottom of the float bowl. As the throttle slide is opening, the velocity of the air coming into the carb creates a suction that pulls extra fuel into the carb through the nozzle.

A – Power Jet Lectron carb showing fuel line coming from float bowl to nozzle sticking down into the intake throat.
B – Regular Lectron carb with opaque float bowl.
C – photo of the 2 styles of floats. The top ones are what slide up and down the 2 posts in the clear float bowl. The bottom one is what is required for the opaque float bowl.
D – photo of the 2 styles of slides. The right one is painted black, the left one is chrome plated.

The original Lectrons came with clear float bowls (as shown in photo A of Power Jet) that had 2 posts coming up from the bottom that 2 independent floats (see photo C) slid up and down on. These were very durable and worked well until leaded gasoline was abolished and gasoline with ethanol (alcohol) was introduced. Alcohol will cause the clear float bowls to soften and distort. This in turn causes the 2 post to move and will affect the movement of the floats. The fix for this problem was the opaque float bowl (as shown in the photo B of the regular Lectron carb). The opaque float bowls do not have the 2 posts in them and require a replacement single unit float (see above photo C).

There were 2 styles of float bowls. The regular style and the Power Jet style. The Power Jet style has a brass connector inserted at the bottom of the bowl to which a thin fuel line is attached (see photo A - Power Jet carb). Both style of bowls are available in the opaque, alcohol proof type.

The Lectron slides are made of aluminum and hold the special needles that determine the fuel and air-metering. The original slides were painted black. These were upgraded later with chrome plating (see photo D). The purpose of these coatings is to prevent the slides from sticking open when under power. Over time and use, both coatings will wear off. If you encounter a sticking slide while riding a bike with a Lectron, the fix will be to remove the slide, clean it and spray it with primer paint. Allow the paint to thoroughly dry (recommended 24 hour waiting time) before installing it.

The Lectron needles are the secret to the Lectron carbs and do away with the different jets and parts found in conventional carbs. The needles are precision ground with a flat side. The length of the needle and it's cut determine the main jet size and mid range fuel delivery. Fine tune adjustments are made by turning the rod in or out of the slide. The needles are threaded at the top to allow this adjustment. The needles are identified with a 2 digit number painted on the round side.