No power for no reason

Previously wrote:

I have a 76 Commando 850, all I have done is take off the battery and fit a new one, upon switching on the ignition - absolutely nothing, on turning the switch to the lights on position then the red and green warning lights come on but nothing else, when pressing the horn button it sounds as thought the battery is flat which it is not.

When turning the ignition switch back to the off and then back to on position - nothing, absolutely nothing.

The only thing I can equate to is that I have replaced the headlamp shell which necessitated disconnecting the internal wires within the shell but I am sure they are all re connected correctly.

I have played about for hours and cannot get a single source of power, the ignition switch is dead, no lights, no nothing. Any ideas, I am no expert but am reasonably competant - this has got me baffled beyond belief.Are ignition switches a common fault?

Suggestions are greatly appreciated in advance - thankyou,

Russell,

Chesterfield

Are you certain the battery is ok? Have you tested the voltage across the terminals?

Hi Russell. My next question is NOT trying to be funny or anything, BUT it's just a case of not knowing what you have: First has the battery got any electrolyte in it? Many batteries are sold without any or without any provided. If it has, have you charged it? Check the open voltage at the terminals it should be somewhere around 13.5V if freshly charged.

Otherwise, work methodically,with a voltmeterkeep one test lead securley on the metal frame or engine and step by step, trace thelive side of the battery along the wiring, testing at any connectorsback to the switches.

Check fuses for corrosion making sure a voltage is the same both sides of them. When you have the headlamp ( or relative equipment) switched on, you can also put your test leads both sides of the fuse to seeif you get a voltage reading, as any voltage drop acrossit will indicate a poor connection at the fuse holder.

Les

Hi Russell,

Provided you can discount the battery as servicable you have to look at the last thing you were fiddling with. In this case the new headlight shell. Ignition switches rarely give problems unless very old. You could eliminate it by substituting a simple toggle switch. My money is on something not connected properly in the new headlight or a poor earth.

Dave

Russell. Don't know if you have sorted it yet, but try the following.

1) Run an Earth wire from the battery (Positive) to the headlight shell to eliminate earthing faults. If things work normally like this then trace the earth fault, by moving the battery end to the frame near the steering column and then headlight bolts. If no joy:

2) Run a a wire directly from the live battery terminal (neagtive) directly to the live side of the ignition switch (white wire side?) this will eliminate the switch.

Les

I had the very same problem with my Mk1. It turned out to be a bad connection inside the fuse holder. I cleaned the connector with the flat blade of en electricians screwdriver. The problem was not the spring loaded side but the other side where the plastic of the holder is moulded onto the metal connector. Make sure this face is clear of plastic around it,s perimeter. This caused an intermittent fault on my bike and took ages to find. Good luck. Andy Finn.