14-0012 Reg/Rec Upgrade For BMW Airheads and Moto Guzzi's w/ Bosch Charging Systems

This guide will provide you with the basic knowledge needed to replace the factory independent voltage regulator and diode board (rectifier) with an integrated 3-phase, Field Excited Reg/Rec that is compatible with both lead-acid and lithium batteries. There are other topics regarding the Airhead charging systems that we'll touch upon in other articles but this one is going to focus on the Reg/Rec upgrade.

Why you should consider upgrading:

Regulator Rectifiers are wear components. Heat is perhaps the most significant offender in causing wear and reg/rec's happen to generate heat in copious amounts. As they age they may have intermittent voltage spikes or produce a constant overvoltage. Inexpensive no-name Reg/Recs often have the same issues like an old worn-out reg/rec or fail soon after installation; make sure you're purchasing from a reliable source with a manufacturer's warranty. 

The Regulator Rectifier that we offer has been optimized for Lithium batteries which require a lower charging set point than lead-acid batteries, 14.5 Volts vs 14.8. It may not sound like much but the difference is enough that over time it will shorten the lifespan of lithium batteries. 

If you're already looking to replace your reg/rec whether it be for peace of mind or a full m.unit installation, using a Lithium optimized Reg/Rec will have you covered regardless of your current battery choice and allow you to switch over without the need to make a second costly Reg/Rec upgrade at a later date.

Before installation:

We suggest testing the charge voltage of the original system and noting stator output before making the transition to the new Reg/Rec in order to confirm your stator is in good working order. It can become more challenging to diagnose charging system issues as you introduce new variables.

Some notes on the diagram:

At this time I've just created a single diagram that shows how this is all integrated with an m.Unit. It should be easy enough to adjust to a standard OEM harness so long as you have your factory diagram as a reference. 

The wire colors alternate year to year model to model, additionally, for some bikes the solenoid and charge light wiring will deviate from our diagram, there's simply no way to represent all the variants so you need to reference this diagram along with your OEM diagram to see the complete picture. I've included a blank wiring diagram in the PDF downloads below if you'd like to trace out a diagram that matches your arrangement and color scheme to file in your records.

Reg/Rec Bosch 1

14-0012 REG_REC+BOSCH.2

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