Uh... What was that? Power loss after bike sat out in rain

[Guest]

So... I hate to say it, but I left my gs650gl out in the rain for 3 days. After the rain started, I had no way to cover it. Won't do that again.

Anyway, I habitually turn off my headlight when starting after it's been a while. It started up just fine, I turned on the headlight, and took off out my driveway.
I immediately felt the bike bog down, so I pulled off the road. I put it up on the stand in neutral, and noticed that the neutral light was dim and pulsing. I tried putting on the choke, and that made no difference, so I switched it off.
I shut off the headlight, and the bike sounded healthier and the neutral light was brighter.

I revved it at a constant 2k or so to get higher alternator output for a minute or so.
I revved it up a little bit and it sounded great, then I pulled the seat and checked to see if the fuses might be wet. None of them were, so I put it back together and flipped on the headlight. Rode it around the lot a little, rode donuts to the left (I turned left out of my driveway).

The problem didn't come back, but I have no idea what it was! Maybe a little moisture somewhere making a minor short in the coils or related circuit? Or just a short in the headlight drawing so much power that the coils didn't have enough power to make good sparks?
I'm glad it's gone.... Hope ti doesn't come back...

[tom203]

Have you got rid of the stator loop to headlight switch?? Water getting in that switch could ground out stator phase limiting charging output. Dimming lights mean low battery ( not being recharged).

[salty_monk]

Idle RPM lower than normal? Could be wet connections but could also be Wet air filter, water in the exhaust creating a restriction etc...

[tkent02]

Have you got rid of the stator loop to headlight switch?? Water getting in that switch could ground out stator phase limiting charging output. Dimming lights mean low battery ( not being recharged).

Best not to get rid of that loop if he still has the operating headlight switch. How strong is the battery? How much did you have to crank it to start it up? When the battery is low the lights will dim at very low RPM when there is not enough power coming from the stator. Same if there is a lot of resistance in some connectors somewhere. Not sure what exactly is wrong, I would certainly go through the tests in the stator papers to find out before something expensive fails.

[tom203]

Best not to get rid of that loop if he still has the operating headlight switch. How strong is the battery? How much did you have to crank it to start it up? When the battery is low the lights will dim at very low RPM when there is not enough power coming from the stator. Same if there is a lot of resistance in some connectors somewhere. Not sure what exactly is wrong, I would certainly go through the tests in the stator papers to find out before something expensive fails.

It's two pole switch- if you bypass the stator loop, you still get to turn headlight on/off if your battery is a poor cranker!

[tkent02]

It's two pole switch- if you bypass the stator loop, you still get to turn headlight on/off if your battery is a poor cranker!

Yes, and if you run the engine with the headlight switched off it makes too much current, the regulator isn't meant to shunt that much current. I may be mistaken, but I believe this is why that loop is there in the first place, so that when the headlight is off only two legs of the stator are in use to prevent excess current from frying the regulator? Removing the loop is a great idea on a newer bike with no such switch. Little help please Posplayer or someone?

[tom203]

Yes, and if you run the engine with the headlight switched off it makes too much current, the regulator isn't meant to shunt that much current. I may be mistaken, but I believe this is why that loop is there in the first place, so that when the headlight is off only two legs of the stator are in use to prevent excess current from frying the regulator? Removing the loop is a great idea on a newer bike with no such switch. Little help please Posplayer or someone?

You are absolutely right, but hopefully we all ride with our headlights on unless we have a sudden charging system failure. By bypassing this loop, my charging output went from 12.6 to 13.8 volts at 3000 rpm.

[tkent02]

Normally a good idea, but not always. I ride a lot of rough roads and dirt roads, a bulb that's lit is a lot more likely to break from the bumpy ride than a filament in an unlit bulb. Also if the light burns out or a fuse fails, I can switch it off to keep from overcooking the regulator or overcharging the battery.

[WilliamGLX81]

Good discussion..

Battery is pretty new, only cranked for about 5 seconds. The idle was normal, but anything off-idle was crap for power.

I did notice some water sitting on the bottom lip of the exhaust tips, but I felt the exhaust streams and they were strong and not spitting water.

Hmmmm. Maybe it was some water in a charging connection. I wonder if there might be a problem with my stator's seal.

Good point about the filament being more delicate on rough roads.

Before I started it, I think the neutral light was normal brightness, but it might have been dim.

[Graham]

I use a leaf blower to dry my GS.