Honda Cub C70 Passport 6 Volt Headlight Voltage Regulator


Honda built the Cub without a Voltage regulator, instead relying on the electrical load of battery and lights to limit Voltage.  If for any reason the battery is not viable or missing, lighting Voltage will skyrocket.  Bulbs blow, especially the expensive headlight bulb.  Once one bulb blows, the rest will blow in rapid succession.

For some unknown reason, with age some Hondas begin producing excess headlight Voltage. Its a mystery why, even after unwinding several stators.  This happens on bikes that have been just fine. Even with a viable battery and all bulbs intact, the Voltage is suddenly too high.

After years of working with these problems, Jon designed a special Voltage regulator to control the excess Volts and prevent headlight and bulb failures.  The device is ruggedized, waterproof, and plugs in. Installation is simple.  Wires and connectors are color matched.  The regulator plugs in without modifications to your Honda’s wiring harness, and fits under the handlebar cover.

July 12, 2014: Eagle-Eyed customer Wayne caught a ground wire error in the instructions… thanks!

The 6 Volt Cub/Passport headlight is powered directly from the engine stator with AC power.
The Pardue Brothers have designed and tested this device to destruction, and it has earned our seal of approval.  We hope it rates as a quality item that Soichiro Honda would have approved of. While the device is simple to install, we recognize that not everyone has extensive wiring experience.
The instructions will guide you step by step thru the simple installation inside the handlebar cover.

PDF Installation Instructions with Photos


This unique device is the result of several years of owning, riding, and repairing Honda C70 Passport motorcycles. This design is for the 1981 and earlier 6 Volt C70, which has a nasty habit of blowing the headlight bulb filaments if the battery is electrically disconnected, missing, or for any reason is unable to accept proper charge.

Some bikes develop higher-than-normal headlight Voltage over time, which is really odd – however we hear about it often.  This product was designed and built to solve the problem.

Jon Pardue spent years developing this part to plug in without altering the wiring.  The part fits under the handlebar cover, installs in minutes and simply plugs in.  No special tools or skills or needed, just a 10mm wrench and a Philips screwdriver.

Honda designed the Honda C70 electrical system to power the headlight with raw, unregulated AC electricity straight from the engine’s dynamo.  Another raw AC output from the dynamo feeds a rectifier to charge the battery, which powers the other lights on the bike.  If the headlight blows, Voltage increases to the battery and other bulbs.  If the other bulbs blow or the battery will not charge, the headlight gets too much power.  You can begin a C70 ride with all the lights working, and have them all blown by the time you finish.  This product won’t keep bulbs from blowing due to normal wear and tear, but it will protect the bulbs so you get decent bulb life.

For less than the price of a new Stanley sealed beam you can install a Pardue Brothers C70 headlight Voltage regulator, and get back to enjoying the ride.  We have color illustrated documentation that can help you assess the need for the regulator.