Red indicator light coming on?

Question;
The red indicator light on my Norton commando keeps coming on while riding it, but when I turn on the running light or headlight, turn signals or stop light the red indicator light go's out. Could it be that with the engine running only, it isn't charging because the battery is fully charged. Any ideas of what is going on?

No that wouldn't be the reason. What model is the bike and does it have the standard electrics set-up with Zenner diode/s and rectifier or has it got electronic charging system fitted?

Check the two leads coming from the inner primary back cover (Stator wires) at the connectors just under the air filter box. Make sure you don't have a wire broken in this location.
Tom
CNN

1973 commando 750. All of the electronics were replace like the Zenner diode and rectifier with solid state. The ignition system are points. The two wires under the air box are connected and are in good condition.

The light stays on until the alternator puts out power. The assimilator tin can is a living joke. There are modern solid state ones. Obviously check output.

Sounds like your solid state unit might have packed up but check all over for bad connections, particularly earth connections.

I also purchase a new assimilator and installed it. Any time I use electrical power for anything, like lights, turn signals, even the horn, the red indicator light will go out. With all electrical off, when I decrease the throttle the red light goes out. When I increase the throttle the red light come back on. I guess If I keep the running light on all the time the red indicator light will then stay off. As long as I keep something on the red light will stay off. I'm going to check my wiring again to see if anything came loose.

When there's an electronic charging unit installed there's not normally a warning light assimilator, the red light gets controlled from the electronics box.
Also check that your battery is not connected the wrong way around!

You need to put a volt meter across the battery to check what happens to battery voltage as the revs rise. It should go up to at least 13.5v

The warning light assimilators simply show that alternator output volts are above battery volts. It sounds to me as if alternator output is down and with the lights on, battery voltage is low enough for alternator output to be higher. Wiring and connections have to be the first thing to check but until you measure it, it's all guesswork.

doesn't sound like it 's wired in correctly. Have you checked the charging system. Is it putting out 14.5 volts or so. The warning light assimilator just lets you know when the charging system is putting current back into the battery. The light will go on when the system is not charging or when you are draining the battery at a rate the charging system can not compete with. The only function that assimilator does is to switch that light on or off based on whether current is flowing into or out of the battery [ Ie it is a sensing switch only ]. It plays no part in the working part of the charging system.
Dereck
Actually, you can ride that bike with the warning light not working. Only thing is, the when it stops charging, you wont know about it till you get a flat battery.;

The red ground lead is connected to the positive terminal and the blue / brown lead to the negative terminal. Looks ok.
I checked the battery before stating the bike and it was 12.5 volts. It had been setting for a couple of months. I turned the key on and the red light came on. I then started it and let it worm up for about 10 minutes with no lights on. I then shut it off and took a battery reading, 13.65 volts. It does look like it is charging. The red indicator light didn't come on at all while running it. I would have ridden it but the roads are pretty muddy.

I recently installed an LED charge light with solid state electronics that does away with that crusty old assimilator. The kit comes from G. B. And was only about $30 including shipping. The LED fits right in the original warning lens holder so external look is the same. It shows a discharge state as proper in situations such as idling with headlights on, and even flashes in case of overcharging.

The whole thing fits right in the headlight bucket (control module is smaller than a small match box) and installs in about 20 minutes with just 2 wires.

I'm very pleased with it and going to order one for my 68 Bonneville to replace the always-on "ignition" indicator lamp

Phil
Austin