Electrical fault?

[courtney]

1965 side points C15

Looking for a fault in the ignition system of my C15. I've tested voltage between ignition switch and light switch and all is good. I'm confident the wiring is correct and the loom is new.

I have gone to set the timing and am using a test lamp to do this according to the book - one wire attached to the engine case, the other to the spring of the points with a battery in the circuit. The light stays on no matter if the points are open or closed. That's not right, is it?

To me it suggests a short but there is nothing apparent touching the engine case or points plate, and I have the insulating washer in the right place. Points and condenser are new. Could either be at fault? Does anyone have any suggestions?

Thanks in advance yet again.

[LightningAndStarfire]

You should have a fat blue spark, if not suspect the coils, leads and caps, plugs. Not sure about the specific demands for Wassell regarding coils etc, did you renew them? Fully charged battery? Cheers

[Rog1]

If the test lamp is staying lit, then the points are either not closing or there is something on the contacting surfaces that doesn't conduct, and when they do close it's stopping the electricity flowing to earth. Try getting a small screwdriver and applying it to the side of the contacts, bridging the gap; the lamp should then go out. You can also try, when the points are supposed to be closed, gently pressing the moving contact towards the fixed one to see if the lamp goes out or maybe flickers.

I assume this is a standard coil and points ignition setup and no electronics are involved. In that case if you are getting a lit lamp, you know at least that there's electricity getting as far as the points and that its not wrongly going to earth, bypassing the points.

[courtney]

Thanks for the replies.

Rog, I don't really understand what you're saying. When the points open the light is supposed to go out, isn't it?

[Colin SS90]

Try disconnecting the wire that goes from the points to the coil.

[Stubaker58]

Hi Courtney,

There are two ways of wiring up the test lamp, with one the light goes out when the points are open, with the other it goes out when they close!

You said you've got a battery in your test set up.  Is this a separate battery to the bike battery? ie do you have a circuit with a battery and bulb such that when you touch the two crocodile clips together you get a light? If so then yes the light should go out when the points open.

Check to make sure you are not bridging the points with the clip on the spring, or that the clip is touching the plate behind. Can you see that the points are in fact opening? You may also need to disconnect the bike battery to get this test arrangement to work.

[courtney]

Hi Stu,

Thanks. I thought I was going mad. The circuit is as you say, separate from the bike and not using the bikes battery. I've completely removed the points plate from the engine and moved the points apart with my fingers. I made sure to check nothing else was touching. All my testing has narrowed it down to this, but I'm baffled.

Colin, what would disconnecting the side from the points to coil do?

[Colin SS90]

The wire to the coil may give you a path to earth and complete the circuit.
With the points plate removed from the engine there must be a problem with the isolation of the points, either there is something touching the spring or contact nut or possibly the condenser is faulty and giving a false earth. I would double check positioning of insulating washers and disconnect the condenser.
Good luck, Colin

[Rog1]

Courtney, I assumed you were using the bike's battery and not a separate one. I've attached a drawing showing each method. I would make very sure the bike's battery was disconnected if using a separate battery, by pulling the fuse.

[courtney]

Thanks Rog. I didn't realise there were two methods of doing it.

Thanks to others for replies as well. I'm probably not going to get a chance to look at it in the week, but assuming it's nothing to do with the points touching anywhere, how would I go about checking the condenser is not the issue?I

I've got a multimeter but a limited, though gradually growing, knowledge of how to use it.

Thanks

[Colin SS90]

Just disconnect it and see if things change. If they do then it's faulty, possibly leaking to earth. If you still have the old condenser try that.
Colin

[Rog1]

Thanks Rog. I didn't realise there were two methods of doing it.

Thanks to others for replies as well. I'm probably not going to get a chance to look at it in the week, but assuming it's nothing to do with the points touching anywhere, how would I go about checking the condenser is not the issue?I

I've got a multimeter but a limited, though gradually growing, knowledge of how to use it.

Thanks

If it's the method using the bike's battery, it's not the condenser. If it's the method using a test battery, it might be. As Colin says, disconnect it. It may not be the condenser itself but it may be the way it is connected.

[courtney]

Thanks both. I'll drag it out tomorrow after work and have a look. I can't relax when I know there's something simple to try like that.

I used the method not with the bikes battery, so it's worth a go.

[courtney]

I have just had a look at this today.

I'm using a battery separate to the bike with the test light. I have checked again the isolation of the points and it is ok. I have also just fitted a new condenser.

With the wire from the condenser to coil disconnected, I attached a clip onto the points spring and one onto the points plate. When I open and close the points with my finger the light goes on and off.

Doing the same, with the clips of the test light on the spring and points plate but with the condenser/coil wire connected the light goes on and off. However,with the test light connected to the points spring and then to the engine case the test light stays on.

What does that suggest is wrong? I was hoping it was going to be the condenser, but it doesn't seem like it is.



As a note, I have converted to 12v and am wondering if anything concerning points/condenser wiring needs altering. I have changed wiring from ignition to light switch and know this to be correct, so I'm ruling that section out. I thought I should mention this although I don't think it's the issue. My loom is also new.

[courtney]

I think I have this sussed out now after checking through it again.

A slightly different issue now. I've moved the auto advance mechanism around on the shaft and can't seem to get it in a good spot for the points to be opening within the range of the slots on the points plate. What is a good starting point for the position of the cam of the auto advance at TDC?