How To: 5th gen VFR regulator rectifier updated with a 919 component.


"Be The Match" Registered
Apr 5, 2006
Utah, USA
06 XTerra, '00 VFR800, '07 ST1300, '11 Multistrada
Part One

If all the connections on your bike are clean and in good condition, you may only need to do this part. It is helpful to put the bike on the center stand for this job, as the side you are working on is on the same side as the side stand.

Head down to your local eBay store and purchase a regulator rectifier from an Honda 919, mine was about $45 and was right between a chipped Elvis collectible plate and a plastic toy from a 1984 McDonald's happy meal priced at $125. The regulator rectifier should have three yellow wires going to a large white connector; four more wires, half green and half red, will go to a second plug.

While waiting for your new regulator, remove the tail bodywork and seat from the VFR. Locate the regulator rectifier on the left side of the bike, it will be gray and have cooling fins on it. Use a 10mm socket to loosen the two bolts, you may need to use a 10mm open end or box wrench on the back of the mounting plate to hold the nuts. Drop one or both of the nuts, curse, and go find them before continuing. The bolts holding on the stock regulator will not be long enough for the new one, they are an M6 1.0 and about 1.5 cm long (I will update this measurement once I go put a tape on them, but I'm too comfortable to do that right now). Head to your preferred hardware emporium and purchase two bolts of the same size and thread pitch, but with a 1cm longer shaft. Taking the hardware you removed makes this much easier. Disconnect the two connectors on the wiring from the regulator. Be gentle, you will need the smaller 2x6 connector later.

OEM mounting bolts do not reach through the 919 regulator rectifier

Longer mounting bolts. Get the same size and thread pitch so you can reuse the nuts

Take a look at both the plugs for the regulators, using a marker, label each side of the VFR's wiring harness. I used "R" for red, "G" for green, "B" for black, and "E" for empty, but whatever works best for you. I also labeled the 919's 2x2 plug.

Label both sides of the plug in case you need to restore to OEM form for some reason. I had already labeled and removed the spades, but here is the wire positions with labels.

Look inside the connector, there is a small notch next to each spade. Using a small screwdriver, depress the spring clip on the spade and gently pull it out of the back of the connector. I found the easiest way to do this was to use the screwdriver as a wedge so I could hold the housing and gently pull on the wire to remove the spade. However, if you are named Zaphod, just depress the clip with your third hand. Remove the smaller housings from both regulators using the above method for each spade. The large white housing with three spades is the same and can stay on.

Notice the small notch above the spade.

Insert a small screwdriver and gently remove the wire from the back

Check the spades on the 919 regulator rectifier. Mine were dirty and had a bit of corrosion, so a bit of emery cloth cleaned them up.

Dirty/corroded contacts as they came out of the labeled 919 connector.

Some fine grit emery cloth cleans up the contacts. Don't take off too much material, just the gunk.

Cleaned contact (above) compared to the dirty one (below)

The larger connector was in similar condition, so a bit of emery cloth wrapped around some cardboard cleaned up the contacts without having to disassemble the housing.

You can use any material you want for this, cardboard was what I had at hand and it worked fine.

Take the 2x3 plug and install the red and green wires into the appropriate slots. If you skipped step three, you will need to look at the connector on the bike to ensure you line up the appropriate wires. Also, don't skip step three. You will notice that the connector had 5 wires going in, but the 919 only has 4 wires to fill it. The black wire is a switched power output that is used as a sensor on the old regulator; this is a stop-gap measure to try to make up for the inherent weakness in the old part. The MOSFET system on the 919 does not require this output and the VFR will run just fine without it. This wire is used by the VFRness to activate the relay for the accessories, we will get to that in Part II.

Focus, you fack!

Plug in the new regulator rectifier to the appropriate plugs and start the motorcycle to ensure everything works.

Install the new regulator rectifier on the bike using the new bolts and existing nuts. The hardware I was able to find late on a Sunday afternoon didn't have the flange from the OEM parts, so I also picked up a couple washers. Install the new part with the wires coming out the bottom of the regulator; the mounting holes are in the same place, so it should bolt right on. Tidy your wiring with a cable tie or two and reinstall the body and seat.

If you are not installing the VFRness with the accessory circuits, you are done.


The Deported
Feb 1, 2007
Dallas, Texas
00 4Runner | 02 919 | 87 XJ6 | 86 CB700SC
A couple counterpoints/comments on your piece, Blind:

- There are actually different "Honda 919" bikes depending on what market you're in and who you're talking to. The regulator/rectifier donor for this is what I ride - the naked/standard bike sold in North America from 2002-2007 as the Honda 919 with an actual model number of CB900F2. This bike was also sold in the rest of the world as the Honda Hornet 900 from 2002 to 2009. It should not be confused with the CBR900RR sportbike variant sometimes called the CBR919. That bike uses essentially the same troubled R/R as the VFR did so swapping it out will do you no good.

- When cleaning the contacts with emery cloth you can get a clean surface for now, but it often removes the gold plating on the connector that provided what corrosion resistance it has. Just check it a few times a year to make sure it's not getting more corrosion, because that's what causes these connectors to melt. A better option I've seen is to use some metal polish and polish away the corrosion gently, leaving the plating intact where possible.

A couple of manufacturers have a special conductive grease designed to improve conductivity and prevent corrosion - this is not di-electric grease! Might be a good idea here; unlike di-electric grease, you apply this stuff directly to the pins or terminals. Most of this stuff is a form of NyoGel:

Ford's version is the easiest to get in the US:

There's also this stuff that some of the more advanced esoteric electronics guys like:

For the plastic-safe lazy man's way to get corrosion off, you can try dunking the connectors in this stuff for a few hours (only the connectors) and see what you get. Available at many auto parts stores and Walmart, this stuff chelates off rust and corrosion. I've not tried it myself for this purpose but I've heard good things about it and used it to good effect on other projects.

- Not all 5th-gen VFRs have the 5 pin/6 slot shell design. 98s and 99s have the same physical connector as the 919 does - a 4 pin connector. The pins may need to be re-ordered to match the 919 regulator/rectifier but the connector is the same. Only the 00-01 5th gen VFRs have this 5 wire/6 pin connector arrangement.

- - - Updated - - -

Also: For those that don't want to buy a used part, the current Honda part number for a 919 regulator/rectifier is 31600-MCZ-003 and as of this writing a local dealer has it in stock for an undiscounted retail price of $151.77. Considering that the known problematic Ricks' Electric aftermarket replacement for the VFR has an MSRP of $149 as I type this...
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