by: Eskort


The regulator/rectifier connector is undersized for the FZ1. It is marginal in its ability to supply the current level that is being demanded when:

  1. The battery state of charge gets low or the battery starts to age and pulls more average current.
  2. An accessory (particularly heated vests, gloves grips) is added to the bike that increases the load.

Several members have only determined this after the connector has melted and the rider gets stranded.


The three white wires in this connector are all above ground and supply the three AC legs of the alternator as an input to the regulator/rectifier. For comparison find the three white wire large connector under the left side cover. This is in series with the burned connector, carries the same amount of current, and has terminals twice the size.

The red and black wires are the current output of the regulator/rectifier and feed the battery and the rest of the electrical system. Note that the charging system is rated for 18 amps of current, and that the type of terminal being used in this connector is generally used in applications of 8-10 amps maximum. So, when you get in a situation where the charging system has to supply current near full capacity for an extended time, the terminals heat up and self destruct, melting the connector shell. This is a common failure on the FZ1 and also the earlier R1 models that shared this design.

This connection system will work well and is adequate to handle heated accessories. This is a low-resistance connector, made of silver-plated copper. The secret of its success is the stainless steel leaf spring built into the plastic housing. This spring applies 25 lb of pressure onto the contacts, ensuring good, vibration-proof contact. Contact resistance has been measured at 600 micro-ohms.

Items Needed:

  1. Three sets of the connector above.
  2. Soldering iron and solder.
  3. Needle nose pliers and wirecutters.
  4. Wire strippers.
  5. Tie Strap.

Installation instructions:

  1. Remove seat, and tank bolt. Prop up tank. If fuel in tank is over 1/4 full, place carburetor drain lines in container to catch the fuel. (I just stick them in the nozzle of my lawnmower gas can).

  2. Disconnect battery.

  3. Cut the connector out, leaving the wires as long as possible.

  4. Assemble connector shells, they slide together. To prevent them from being plugged in incorrectly, orient the two shells for red and black horizontally and the three shells for the 3 white wires vertically.

  5. Prepare the wires by stripping 1/4 inch.

  6. Solder the terminals on.

  7. Insert terminals through back of shell after orienting the end of the terminals to be parallel to and on the same side as the metallic spring. The spring can be seen through the face of the connector (see below).

    Make sure that the red is in red and the black is in black. The order of the three white wires does not matter. They can mate with any of the three white wires to the regulator.

  8. Mate the connectors and tie strap the connector together.

  9. Reconnect the battery and lower and bolt the tank down.

  10. Start the bike and monitor the battery voltage. With a fully charged battery, the voltage should be about 13.2 +/- 0.2 at idle, and by 2000 rpm should be at 13.8 +/- 0.1.

The information presented here reflects solely my personal experience with my motorcycle and is presented for entertainment purposes only. No information presented here is to be relied upon for issues of rider safety or to replace the services of a qualified service technician. Any attempts to follow or duplicate any of these procedures are done so completely at your own risk. By reading the information on this site, you agree to assume complete responsibility for any and all actual or consequential damages that may arise from any information presented herein.