550gs runs great till I turn the headlights on.

[Anonymous]

I have a 1980 gs550 that runs great as long as the headlight is not on! once on It seems to put a tremendous pull on the engine, will die when idleing and any time I stop. I have tried adjusting the idle up but that doesnt help. I dont feel safe with out it> I keep reading about bad grounds on these, but I dont really understand how to do it. Would the ground cause this problem, if not what would?
Thanks Chuck

[Anonymous]

Headlight usually kicks in the third leg of the stator. Your charging system probably can't handle the headlight. 65 watts = 5 amps + the tail light. (a substantial load on a 18 amp system) I would look at the battery voltage with the engine off, then again after you start it. Should go up to about 14 volts running. If it doesn't then go to the charging system troubleshooting section of this site. If it looks okay until you turn the headlight, it could still be a weak charging system that can't handle the additional load, or the light switch isn't kicking in the third leg. Your battery could also be coming to the end of it's life. My rule of thumb, if the battery is over two years old or I don't know it's age, and I'm having a problem, get rid of it. It's a disposable part of the charging system.

[Anonymous]

the battery is new. I will go to the troulbe shooting section as you suggetsed and work from there.
thanks chuck

[crc1214]

Hold it right there my man!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!
Assuming no charging problems occur and everything checks out under the "no-load" condition test........ read on.

Exact same thing happened on my 550.

It is the headlight switch. It's not completing the circuit needed to send full stator power to the reg/rect.

Look at your wiring diagram, and see what two wires (one FROM the stator, and one TO the reg/rect unit (or, on my 78 550, just the rectifier - my reg and rect are seperate)) are connected when the headlight switch is turned to the "on" position.

Then, just manually hook these two wires up yourself. You can access them below your seat, below the tool kit holder, in a large rubber bell-shaped boot.

On mine, it was the green/white wire FROM the stator, and I connected it to the red/white wire going TO the rectifier. Should be the same on yours, but check a wiring diagram just to be sure. Just connect those wires, and the stator will be sending full output to the rectifier at all times.

Now...... keep in mind......... ALL TIMES. That means DO NOT accidently turn your lights off. Then you will be overcharging your battery.

Hope this helps...... something tells me it'll do the trick. Let us know.

Chad
Columbus, OH 1978 (same year as me) GS550E

[crc1214]

Tell you what......... sounds like you are just starting out now that I re-read your post.

I notice the bike is a 80 gs550. I'll look in my clymer manual at the wiring diagram for yours and let you know what two wires I'm talking about.

Chad
Columbus, OH 1978 GS550E

[crc1214]

Well I'll be damned. Just learned something new while looking this info up.

The 1980 "E" model used seperate regulator and rectifier units just like my 78.

But the "L' model used a combined regulator/rectifier unit! Weird!

Doesn't matter......... for what ails you anyway.

The two wires you need are indeed the green/white wire FROM the stator, and the red/white wire to the rectifier (if your's is the "E" model) or the combined reg/rect unit (if your's is the "L" model).

To be more clear.......... take all the wires out of that rubber bell shaped boot that I spoke of, and first locate these wires. Then disconnect them where they are currently connected.

Take the MALE end of the green/white wire, and connect it directly to the FEMALE end of the red/white wire.

You have just done what your faulty headlight switch once did.

Chad
Columbus, OH 1978 (same year as me) GS550E

[Anonymous]

you are the man! I'll do it today and let you know.

[Anonymous]

Tried to tell you that in my post, the third leg of the stator goes through the headlight switch. So if it isn't connecting, you're putting the headlight load on the system without the additional current supply. Pay attention to what Chad said, if you wire the stator direct, you must have the headlight on (all the time).

[Anonymous]

You all are a great help! Being new to riding, I assume it wouldn't be a bad thing to have the headlight on all the time would it? most of the bikes I see around town seem to always have them on.
thanks again,
Chuck

[Anonymous]

It's a law here but some people (with weak charging systems, I assume) ride without it.

[crc1214]

Yes, definetely ride with your lights on all the time! If you are in the US, it's the law in all 50 states I believe. When I had that charging problem with my 550, I would just turn my lights off on the country roads so I could get a good charge - BIG mistake!

The 5 or 6 times I rode like this I had two near-accidents with cars pulling out in front of me. I even ride with a bright red jacket, but it didn't help!

So definetely ride with those lights on - even if it's not the law where you live. You will be a LOT more visible to other drivers! After all, classic GS's are meant to be seen!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!

Chad
Columbus, OH 1978 (same year as me) GS550E

[Anonymous]

I put in a relay in the third leg of the stator, so turning on the headlight switch energizes the relay and closes that leg of the stator.

I also put in a relay (energized by the same control wire) that turns the headlights on/off. Then I added a third relay to select lo beam or hi beam, with all new 14 ga wire going to the headlight.

Seems like a lot of work, but I now have virtually no current going through the handlebar switch--only the relay control current, and the headlights work better than they have in 15 years. I had been contemplating putting in a brighter bulb: if I want to I can, now I know the wiring can handle it, but guess what? With the new wiring and good contacts through the relays, the existing bulb is nice and bright. And all of these modifications are completely "transparent," all switches and controls operate in the same manner as the original design.

[Anonymous]

Well now that you all have given me all this great advice I went home to do the basic rewiring and decided to go for a ride first. I rode about 2 hours around town, with the headlight on and it ran like a top. the light is as bright as it can be and it is idleing perfect. I even rode to work this morning (hopeing it would not run right) and no problems. Let me tell you this is my first bike and I know nothing about them, but is it possible that there is just a loose conection or a bad ground? this bike was sitting for several years before I got it so Im assuming there could be some corrosion at some of the connections.
Thankyou
Chuck

[Anonymous]

I'd suspect a loose connection, corroded battery cable, or bad ground. Or a combination of any of these. A little preventive maintenance here will help avoid future problems--like being stuck on the side of the road, or having the rectifier/regulator go out. Enjoy!