Noob looking for Regulator Info

SinisterMatti

XS650 Enthusiast
Messages
55
Reaction score
2
Points
6
Location
Great Falls, MT
Hey all. I bought my 1978 XS650e last month and have really enjoyed working on it, but I've run into a problem that has stumped me.

First, some background. When I bought the bike, it wasn't getting any power, the cables on all the lights and blinkers were either disconnected or cut. I took the battery to a local shop and had it charged. I rode the bike a few times, and then let it sit for roughly 2 weeks while the tank was being painted and the seat reupholstered. When I went to start it after getting my parts back I discovered that the batter had gone dead again. I went out and bought a new battery. Everything seemed to be fine, until I made the mistake of pressure spraying the lower half of the bike. Immediately after the wash my electronic starter would not respond at all. It's almost as if the button isn't connected. My kick starter is hit or miss (it frequently spins free and won't turn over the motor) so I ended up run starting it to make it home. The next morning my new battery wasn't giving any power. the multimeter read it at 4 volts. I tested and charged it, but it seems I have a charging issue.

The service manual reads at 2k RPM the battery should be at 14.5v, but the highest i've been able to get it to, even going to 3k rpm is 12.7v. I did the wrench tap test with the bike running and there is a magnetic field on the alternator cover when the bike is running.

This is as far as I've been able to take it. I've been trying to research this, but frankly a lot of the how to's are simply over my head. I'd like to try replacing the regulator as that seems to be a frequent weak point in a lot of the threads i've been reading, but I've been unable to find anywhere online that sells an older style regulator. I'm very visual and i'm having a very hard time comprehending the steps for upgrading to the newer style regulator.

I'm sorry for the long rambling post, but I've run out of ideas. I'm open to any suggestions, including a source for a new/refurbished regulator in the older style, if such a beast exists.

Thanks for reading.
 
The old mechanical regulator on your 78 is probably worn out and needs to be retired. They can be adjusted, but its really not worth it as it will just go out of adjustment again.The old stock rectifier, is of an old design, and also needs to be replaced.

Here is a link that will explain all the detail you need:
http://www.xs650.com/forum/showthread.php?t=21485

The VR-115 should be available on E-bay. Same thing for a 3 phase rectifier.

These components work really well, and are less costly than places such as Mikesxs.
 
Thank you for the quick reply.

So on the stock regulator there is a black, yellow, and red/white wire. These run to the rectifier, which is mounted on the underside of the battery compartment, as i understand it. is it on the other side of the rectifier that the Black, yellow and red/white wires turn into the black, brown and green you mentioned in your post?
 
The item with the yellow ,black and red/white wires is the safety relay. The regulator is under the left side cover.
 

Yes, the regulator and rectifier you reference will work just fine for you. Shop around on E-bay, you may find the VR-115 cheaper.

If you had carefully read the thread that I posted, you would realize that you don't need any nylon screws.

Pay attention to what Grinder said.
 
You won't need the nylon screws for the brushes. That's a mod for using a later model's type regulator on your earlier style alternator. The VR-115 is compatible with your alternator just the way it is, no need to change the brush mount screws to nylon.
 

Hey, I just ordered on from Rockauto, from my '79 about a week or so back. But I ordered the WELLS one. Part Number was vr727 I believe, but it's listed as a direct replacement for the VR115. I found it listed in one of the threads on here.

Anyway, it was half the price of the VR115, at about $13 on closeout. If you haven't ordered yet, might want to take a look. They had it to my door in 2 days and it's stamped made in USA.
 
Thank you everyone! This makes a lot more sense now. @retiredgentleman Thanks for clarifying. On that thread further down someone had posted that how to, and I misunderstood. This makes so much more sense now that I know the regulator is on the left side. Thanks Grinder!. I took my bike to the local yamaha shop and they told me the regulator was on the right hand side. @pkovo I haven't ordered yet. Did you install the VR727 yet? How is it working for you?
 
The item with the yellow ,black and red/white wires is the safety relay. The regulator is under the left side cover.

What is the safety relay? My battery has been draining itself, and every time i disconnect or reconnect the battery it clicks. Is it supposed to have power when the key is off/removed?
 
Thank you everyone! This makes a lot more sense now. @retiredgentleman Thanks for clarifying. On that thread further down someone had posted that how to, and I misunderstood. This makes so much more sense now that I know the regulator is on the left side. Thanks Grinder!. I took my bike to the local yamaha shop and they told me the regulator was on the right hand side. @pkovo I haven't ordered yet. Did you install the VR727 yet? How is it working for you?

Yes, got it installed and it's working well. I'm fighting slightly high charging voltage, but thanks to this forum I understand why and how to cure it.

You have to get slightly creative mounting it because it doesn't match the old holes, but if you search threads you'll see how most do it.

I've had my xs for over 20 yrs, but just recently pulled it out of the garage cocoon where it's been neglected for years. I've adjusted that old original regulator before, and it's no fun. I was very happy to find the information on this easy replacement. In my opinion, it's worth it regardless of whether it's the source of your charging problems or not.
 
What is the safety relay? My battery has been draining itself, and every time i disconnect or reconnect the battery it clicks. Is it supposed to have power when the key is off/removed?

The Safety Relay does 2 things. Once the engine starts, and the alternator produces voltage on the yellow wire, the SR turns on the headlight. It also disconnects the voltage to the starter motor solenoid.
 
The Safety Relay does 2 things. Once the engine starts, and the alternator produces voltage on the yellow wire, the SR turns on the headlight. It also disconnects the voltage to the starter motor solenoid.

That's very helpful! Thanks once again. My starter hasn't been initiating since I washed my bike last, so I suspect either a bad starter solenoid or a bad safety relay.
 
FYI, Shipping on that one is about 2 weeks. I ordered it from same seller on 4/13. It's not been delivered yet, but I was notified it arrived in the US 2 days ago.
 
Received the Voltage regulator yesterday. That was quick! I've been keeping an eye on the battery level, and despite my riding it the battery is maintaining. Still can't break 12.7v, but at least it's still alive.
 
Back
Top