Ignition warning light problem

Don't know of any tests other than substituting with known working example but if its the original then its well past its use by date, not exactly long lasting. Go for a solid state alternative, Al Osborne does one and RGM.

Is that the blue thing

No, that's the 2MC capacitor for battery less running, pre mk3 charging warning cans are silver/grey.

I have a Mark 3 and when on a long trip abroad the battery was discharging, albeit slowly, someone suggested that it may be caused by a faulty warning light assimilator so I disconnected it. The warning light stayed on after that but the charging problem was resolved. Logically therefore a faulty warning light assimilator could cause the warning light to stay on. They can be unreliable and I would change it. Even it isn't the problem you will have a potentially useful spare.

For those who are having trouble with warning light not coming on when switching ignition on - check the bulb/ socket and connections in headlamp shell . That was the problem with mine.

Have a similar problem on my MK 3 850 with the red charge warning light sometimes not coming on when ignition switched on prior to starting - sometimes it does , sometimes it doesn't. When engine starts it always goes out however unless revs are at very low tickover when it just flickers a bit - blipping throttle puts it out again. Been like that for yearsand battery charging system has always been OK. I did once replace the assimilator (black thing on the MK 3)which cured the problem for a while but it has recently started playing up the same again. Fitting a new assimilator will likely cure your problem.

My headlight shell has a lamp but it's not connected to anything.

I can recommend the charge warning light kit sold by this guy

http://www.improvingclassicmotorcycles.com/products.htm

I fitted the the standard charge warning light to my friends 850mk3 when his assimilator packed up. I have the charge/oil warning light unit on my MK3. For pre mk3 models I think the deluxe charge kit is the way to go.

Regards

I fitted a charge warning light to my 650 because the ammeter would only stop showing a discharge, without lights, at over 50 mph. The charge light proved the ammeter correct and problem detected to the slightly smaller rotor. (Not much in it) I bought my warning unit from Paul Goff, but I understand that he is supplied by Alan Osborne.

Kattherine. I have a Mk 3 Commando and I'm most interested in the oil warning light you mentioned. (Charge light unit still working well after all these years)

I have just fitted one of those warning lamp kit from improving classic motorcycles works a treat. But the light came on after about 30 minutes of riding then kept coming on and going off intermittently throughout the ride.

Anyone got I idea as to the cause. I've checked the connections on the rectifier

Thanks Alan

If the light is working as advertised and the light keeps coming on you may have a charging issue, you need to get the multimeter out and get testing. If you run with lights on and the light comes on at lows revs and goes out as the engine speed increases you either live with it, fit a higher output alternator, or go LED on the lights which is what I have done. My light was coming on at junctions with flashers running and dipped beam, switched to leds and it now never comes on, the latest LED's have sorted out the beam pattern which was bad previously.

They best thing about the assimilator is that you can throw them a long way.

Google it and it brings you to answers on this site.

Yes, you could use it to play fetch, if you have a dog! As I recall, I emptied my assimilator years ago and fitted a generic relay in there, I've had no trouble with it since. When the voltage gets up, the relay switches the light off. I just had to cut a slot in the end cover for the extra spade terminal on the relay. Just a thought ...

Previously martyn_hambling wrote:

Hi

I have a 74 850 Roadster.

The ignition warning light is staying on whilst running.

I have checked the alternator charging and it seems to be ok.i.e current going into the battery at different rates with load (lights) on and off.

Im thinking it may be the way Ning light assimilator at fault.

What is the test procedure to prove this?

i should add, prior to this (weeks before) I noticed that the warning light was not coming on immediately the ignition was switched on, which makes me think the assimalator was failing.

Any thoughts welcome.

Martyn

There is a way mentioned in the workshop manual but I thinks its for when the light is not coming on.

The Universal fit Charge Warning light with 10mmTRI-colour LED - £12.13 inc UK P&P

These are supplied by : IMPROVING CLASSIC MOTORCYCLES.COM