F650 VR Relocation FAQ

edited by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.
Last Updated: 05 January 2007, by Winter #1935

For other related FAQs:


The Voltage Rectifier (VR) on the Classic is not located in the most ideal location. The lack of airflow is probably one fact in why so many of the Classic VRs fail. This FAQ contains information on how to relocate your VR to a better spot. (This problem does not affect the GS models, as the VR is located on the RHS up near the bash plate).

Better Solution: Install a GS Voltage Rectifier
There is now a far better solution to the VR problems associated with the Classic VR. Install a GS VR as discussed in the Voltage Rectifier FAQ. The GS VR is a much better alternative, and should also be relocated (as per the installation instructions in the VR FAQ). This FAQ is provided for Information Purposes only. It is HIGHLY recommended you install and relocate a GS VR

The Voltage Rectifier/Regulator Relocation Project

by Flash #412


The voltage regulator / rectifier (VR) comes from the factory bolted to the top of the rear fender, under the seat, no where near any air flow. This thing has fins for a reason, because it gets hot. Having it stuffed up under the seat does not cool it very effectively. The stock configuration includes a snorkel sticking out of a big hole in the airbox under the right side cover. Removing this rubber snorkel is simple.(See Note 1 Below). You just squeeze it and pull it out of the hole. However, you will then need to take the tops off your carbs and drop the needles (physically) one notch (See Note 2 Below). You can do this with the carbs in place. It is easy but not covered here. If you do that, you get a little more intake noise and maybe a little bit more power. You also get a big place where the snorkel used to be to which you can relocate your VR. This will put it in a position where the fins will get some air flow even at idle, due if nothing else than to the air intake being right next to it. Furthermore, the chimney effect (See note 4 Below) of the fins will be able to work as they will be oriented vertically. The picture below shows the VR in it's original position as well as the Big Hole in the airbox where the snorkel used to reside. The white (burp) tank is for the radiator overflow. We're going to use two of the three bolts mounting that to mount a bracket for the VR.


The bracket I got was made of galvanized sheet metal. I don't have a drawing for it because someone else made it and sent it to me. If I do get a dimensioned drawing, I'll add it here. The burp tank is mounted with three tinnerman nuts. I removed two of them and threw them in my spares kit. I removed the bolts and put them in the trash. I used some REAL bolts and some Nyloc nuts instead. The picture below shows the bracket from a couple of angles. You must be careful that you don't end up with the VR in contact with the burp tank. If you do... the burp tank will quickly get a hole in it, I'm sure.

On thing that happens is that the ground wire (See note 3 Below) will no longer reach the stock mount from the new location. Since I am not using tinnerman nuts, I just scratched the paint away where the ground fitting was going to go in order to make SURE that it is in good contact with the frame. I checked it with a meter between the fitting and the motor, after tightening the bolt. It has GOOD contact. Refer the Misc Electrical Q's FAQ for Ground testing.

After getting the bracket mounted, you can use the nuts and bolts from your original VR mounting to relocate it. (I changed mine to real bolts a while back.) Below are a few shots of the VR in the new position. You can see that the wires snake nicely between the airbox and the frame and reach their mating connectors quite nicely. Notice how the fins are in a vertical orientation for improved cooling in still air. The shot from the top shows how the VR is inside the contour of the side cover. You can also see how there is now additional under-seat storage area. Although I'll probably clean up where the VR used to be and slap some duct tape over the holes before storing more stuff there.

The photo below is not a very good shot. But it was the best I could do. There is plenty of clearance between the side cover and the VR. I am confident that the VR will be much happier and cooler in its new home.

Note 1: On Removing the Snorkel:

Note 2: On Dropping the Needles :

Note 3: On Lengthening the (Brown) Ground Wire to Ground in the OEM Location:

Note 4: Fin Orientation

The Question:

Since we received two more feet of snow, I have decided to relocate the VR before the riding season starts. I've looked at the FAQ, and decided to go with Mark's and Kristian's suggestion to cut down the snorkel, rather than remove it. Now, Flash suggests to mount the VR with the fins in a vertical position. Wouldn't it be more efficient to mount it with the fins horizontal? Any suggestions?

The Voltage Rectifier/Regulator Relocation Project - Alternative #1
by Prof #001, with feedback from Erin & Chris Ratay
November 25, 02

The rectifier is an electrical device that regulates the voltage generated by the stator. On older F650 models the rectifier is located directly under the seat. It is the finned metal object, black in color, and secured with two 10mm bolts/nuts. There are three yellow wires bundled together, one brown wire, and a red/white and green wire bundled together coming out of the rectifier. The rectifier needs cooling for proper operation and this stock location does not provide adequate cooling.

The problem of relocating the rectifier is four-fold:

1. safety from road debris and moving parts,

2. airflow for cooling,

3. avoiding cutting/splicing wiring, and

4. where to drill mounting holes.

After a great deal of consideration and thought, it all came together. All problems were solved by relocating the rectifier on the underside of the flashing on the right side of the bike. Please refer to the pictures as marked.


Feedback #1

I hereby nominate myself to be Wingnut of the Week. Last weekend I relocated my Voltage Regulator. I coulda swore I checked the ground's new location to make sure it had continuity with the negative pole of the battery.

When I parked, I put the fork lock on and inadvertently put the parking lights on. About three hours went by and when I went to start the bike, there was just enough power to get one rev outta the battery but I heard the exhaust valve decompressor click and the bike started right up. Whew, so glad I didn't have to bump start, my foot is lame and I had A LOT of pirate gear. I knew battery power was low because the dash lights were dim, but I made it the 12 miles home, with the headlight on (I didn't want to be stopped and the NYC Highway Patrol is on the hunt for revenue). I took the battery into my apt. to charge it up. It was down to 11 volts and none (that's right, zero) of the balls in my hydrometer were floating on all cells.

I looked in my notes and sure enough, this Wal-Mart battery had gone 12,000 miles in 20 months. The original battery crapped out at 13,000 miles in 17 months. I guess I was due for a replacement. Rode the Guzzi to Wal-Mart and bought an even cheaper battery than before (unfortunately, for the same price). I installed the new battery after a proper set-up and initial charge.
Just to make sure, I checked the voltage at the battery while the bike was running, 12.4 volts. This is not right. I grabbed my official Italian-bike ground check wire (standard tool on Guzzis), which is basically a piece of phone wire left by the phone company guys in the alleyway where I park. Put one end on the VR ground and the other on the battery and lo and behold, the battery voltage shot up to 14.25. Hmmmmm, I guess I really didn't check that the new VR ground position was properly grounded.

What I find hard to believe is that the old battery, which I'm certain I killed prematurely, Ged Rest It's Plates, ran for a whole week, 125 miles without being recharged. And those were all city miles, often with headlight on, brake light activated, turn signal on and fan on waiting at a traffic light.

So, for not properly checking the ground I killed my battery, unduly stressed my charging system, and spent thirty-five green USA dollars on a new battery. I think I deserve this week's Wingnut of the Week Award. Thank you. Shank.