Started my bike today, and charge light stayed on.

[King Herald]

1997 r1100r, 103,000 miles, never had a charging problem before. 

 

I've checked the belt is still in one piece, and it feels fairly tight.

 

I got a wrench on the alternator pulley and it took some effort to turn it so I don't think the belt is slipping. 

 

Reading a good few old posts it sounds like an alternator failure is unlikely, so I guess checking connectors and wiring is the next step. 

 

It's doubly annoying actually, as I've just put a new front tyre on, cleaned the pistons/calipers up as they were dragging a bit..... and the test ride fell at the first hurdle.....

 

Plus, I'm just 3 miles into a tank full of fuel, and I'm sure the tank will need to come off.

[Hosstage]

Check voltage at the battery, standing and running to verify a real problem. Check the last thing you were working on as this happened after you worked on it (might be a loose connector, etc.)

Dr will chime in soon, I hope, to give you better direction.

[King Herald]

5 minutes ago, Hosstage said:

Check voltage at the battery, standing and running to verify a real problem. Check the last thing you were working on as this happened after you worked on it (might be a loose connector, etc.)

Dr will chime in soon, I hope, to give you better direction.

I'll do that tomorrow, it was getting dark as I was preparing to ride tonight. I'll start with tightening the belt up, and go from there. 

 

Yesterday there was no problem, no charge light anomalies, and all I've done since then is drop the front wheel out and reinstalled it. And the motor started immediately, like it always has. 

 

 

[Jim Moore]

Did you try revving the engine a little bit? I had an oilhead that would do that if I didn't rev the engine after start.

[dirtrider]

12 hours ago, King Herald said:

1997 r1100r, 103,000 miles, never had a charging problem before. 

 

I've checked the belt is still in one piece, and it feels fairly tight.

 

I got a wrench on the alternator pulley and it took some effort to turn it so I don't think the belt is slipping. 

 

Reading a good few old posts it sounds like an alternator failure is unlikely, so I guess checking connectors and wiring is the next step. 

 

It's doubly annoying actually, as I've just put a new front tyre on, cleaned the pistons/calipers up as they were dragging a bit..... and the test ride fell at the first hurdle.....

 

Plus, I'm just 3 miles into a tank full of fuel, and I'm sure the tank will need to come off.

Morning  King Herald

 

That charging light is a pretty simple circuit, the ignition switch 12v is put on one side of that dash warning light bulb & the alternator regulator is connected to the other side of that bulb. So if the alternator is charging below the voltage that the ignition switch is supplying from the battery then the light comes on. 

 

So if your light is on then you either have  a short to ground in the alternator side on that warning light circuit (not likely but slightly possible). OR there is something wrong with your alternator or voltage regulator (or the belt isn't spinning the alternator pulley). If the belt in on the pullies & somewhat tight then then they will usually charge enough to put the light out. 

 

If you can access the alternator just unplug the connector with the blue wire then with the key ON see if the light is out, if so then you have an alternator problem. 

[King Herald]

Morning DR,

Very strange, but today I went out armed with tools and multimeter, measured the voltage to the battery, 13.1v and then  fired the bike up. The red light went out almost immediately as it was on high idle, cold start. Voltage goes to 13.8 with the rpm at 3k or so. 

 

I've adjusted the belt a touch, it wasn't loose per se, but I could easily twist it over 90°.

 

I shall remember what you have said about the blue wired connector, in case the problem comes back. Thanks for the info.

 

I think my charge voltage is low, so something may be going on. The battery was new two years ago. 

[King Herald]

2 hours ago, Jim Moore said:

Did you try revving the engine a little bit? I had an oilhead that would do that if I didn't rev the engine after start.

 

I couldn't do that too much last night, it was pretty late and I have elderly neighbours. It may have cured the whole issue if I had, but I'm so used to the charge light going off immediately. 

[dirtrider]

30 minutes ago, King Herald said:

Morning DR,

Very strange, but today I went out armed with tools and multimeter, measured the voltage to the battery, 13.1v and then  fired the bike up. The red light went out almost immediately as it was on high idle, cold start. Voltage goes to 13.8 with the rpm at 3k or so. 

 

I've adjusted the belt a touch, it wasn't loose per se, but I could easily twist it over 90°.

 

I shall remember what you have said about the blue wired connector, in case the problem comes back. Thanks for the info.

 

I think my charge voltage is low, so something may be going on. The battery was new two years ago. 

Morning  King Herald

 

Just keep an eye on it, if you have worn alternator brushes sometimes one will hang up slightly so after shutting off a hot engine (hot alternator) the bush can lose contact with the rotor slip ring until the alternator either heats up a little or engine vibration dislodges the brush.   

 

The light staying on can also indicate a failed diode in the regulator or failed diode in the rectifier but that typically doesn't start working again by itself.  

 

With 103,000 miles you might look into installing a new regulator & brush assembly (can be done with alternator in place but it is a REAL pain to do)

[King Herald]

Morning DR, I need to pull the tank at some stage, my rubber hoses have been in there six years now so I plan to change them out. I shall have a good look at the alternator brushes etc while the tank is off. 

[Michaelr11]

8 hours ago, King Herald said:

think my charge voltage is low, so something may be going on. The battery was new two years ago. 

13.8 volts is very normal output for an unmodified Oilhead alternator.

 

[King Herald]

14 hours ago, Michaelr11 said:

13.8 volts is very normal output for an unmodified Oilhead alternator.

 

 

That's good to know then, thanks.