Author Topic: C11G 54 no spark  (Read 840 times)

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Offline gsseirik

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C11G 54 no spark
« on: July 12, 2019, 07:02:04 am »
Hi! I inherited a BSA c11g from my grandfather. He bought this bike in boxes, and restored it. Every part of the bike has been restored. The only thing he had problem with was the electrical system and main loom. He told me that he might have done some incorrect connections, and that maby led to a overload of any of the components. He gave up the whole project, and bought a new restoring project. Im wondering where to start the troubleshooting? Test the condenser and the coil with a mulitmeter? Regards from Eirik

Online Ginge

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Re: C11G 54 no spark
« Reply #1 on: July 13, 2019, 09:51:25 am »
If it still has the original ignition system incorrect connections will probably only hurt the battery.  If it has electronic ignition incorrect connections may have damaged them.

Unplug the alternator from the system, remove the head light and tail light bulbs. Disconnect the horn and any brake light switch.

Everything left connected is ignition ( coils, points, plugs ) and the rectifier.

Start with a charged battery.  Make sure it is properly grounded (earthed) to the frame.  Use the multimeter to confirm.  Now check that you are getting power to the ignition switch ( possibly via an ammeter ) and then power to the the points when the ignition switch is turned on.  Also check power to the coil when ignition switch is turned on.

Look at the manuals on the forum and make sure the points assembly is correctly built.  There are some tricky insulating washers that need to be in the correct place.

Do you get a spark at the points when you kick the bike over?

Are the points opening and closing?
Ginge.

Offline Faster

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Re: C11G 54 no spark
« Reply #2 on: July 13, 2019, 10:12:04 pm »
Nicely explained Ginge  ;)

Offline gsseirik

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Re: C11G 54 no spark
« Reply #3 on: July 14, 2019, 08:30:46 am »
Thank you very much for the thorough explanation Ginge. I'm looking forward to get it running:-)

Offline gsseirik

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Re: C11G 54 no spark
« Reply #4 on: July 14, 2019, 08:43:44 am »
There is a zener diode. Is this a part of the original electrical system on c11g?

Offline timsdad

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Re: C11G 54 no spark
« Reply #5 on: July 14, 2019, 09:08:36 am »
If there's a Zenor diode then the system must have been converted to twelve volts and the alternator is not wired through the switches.

If so, it will need 12 volt bulbs, battery and coil and can be confirmed by checking if the bulbs are already 6 volt or 12 volt. The coil may also have 12 volts stamped on it somewhere if it has been replaced. The old original 6 volt coils usually had SW and CB marked on the top but all later ones will have had + and - on them.


Ray
Just a motorcyclist.

Offline gsseirik

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Re: C11G 54 no spark
« Reply #6 on: July 14, 2019, 09:16:12 am »
Thanks for the input Ray! Very helpful. So then is it possible that there have been an overload to any of these components?

Online Ginge

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Re: C11G 54 no spark
« Reply #7 on: July 14, 2019, 11:47:31 am »
Your bike was originally six volt, positive earth.  Charging regulation was done by switching the coils inside the alternator ( via the ignition switch ). I have never heard of a six volt British bike being fitted with a zener so as Ray says, your bike has possibly been converted to 12volt and rewired.

The zener will fail if wired incorrectly, but that won't stop spark.  It will just mean that excess current from the alternator/ rectifier goes to battery and overcharges it ( instead of being converted to heat by the zener).

I think you should tell us more about the electrical components on your bike.  Especially battery, coil, alternator and rectifier.

Ginge.

Offline gsseirik

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Re: C11G 54 no spark
« Reply #8 on: July 14, 2019, 04:01:31 pm »
Thanks for the reply Ginge. I don't have the bike at home yet, and I'll check out the components tomorrow.

Offline timsdad

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Re: C11G 54 no spark
« Reply #9 on: July 14, 2019, 06:07:19 pm »
It will be easier to just wire it to 12 volts, Eirik, if it hasn't already been done, because the wiring will be much simpler. As well as the zenor diode, it will need a little modern, square, solid-state rectifier, costing about £5 Sterling off e-bay, the 12 volt battery, bulbs and possibly a coil if Grandfather hasn't already bought these. All the rest will cope with 6 or 12 volts.

Ray
Just a motorcyclist.

Offline gsseirik

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Re: C11G 54 no spark
« Reply #10 on: July 14, 2019, 06:48:29 pm »
Thanks for the tips Ray! I haven't looked at the components yet, since I need to move the bike to my house before I can start working on it. Im gonna go by the storage tomorrow and check. I think it was converted to 12 volts earlier by someone else, since it already has a zenor diode. But I don't know if its done with the right components. So I need to check the inscriptions/specifications on the coil, rectifier, battery and bulbs?

My grandfather re-assemblied the bike from boxes, and did all the mechanical work. When it didn't spark he put it away, and later  on gave it to me. I think he used several hours of troubleshooting on the electrical system. He is now working on a Royal Enfield instead. A lot of documents came with the BSA, but it all looks like the same parts-lists and manuals that you could find in this forum. And a copy of "Monthly Old Bike Mart" issue 32 February 1988.
« Last Edit: July 14, 2019, 07:07:55 pm by gsseirik »

Offline gsseirik

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Re: C11G 54 no spark
« Reply #11 on: July 14, 2019, 07:03:29 pm »
Here is a chart my grandfather made to try to understand or to make it work. I think this is how he has connected it all.

Offline Faster

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Re: C11G 54 no spark
« Reply #12 on: July 15, 2019, 02:25:41 am »
Hi

From the drawing it's an 12V circuit . Check on the battery too . You have to make sure the battery it's not dead .
Somehow 12V circuits are more stable . The diagram made from your grandfather seem to be correct . I think that you have a Lucas PRS8 switch that controls
lights and ignition . There is several connections on it . You can check those on the diagram that I am sending to you which is basic as yours . The differences may be voltage and the zener diode . Again , you have plenty of good knowledge over here in this forum that will help you to sort it out the situation . Good luck

https://bsac10c11c12.co.uk/smf/wiring-diagrams-91/lucas-c11g-wiring-diagram/new/#new
« Last Edit: July 15, 2019, 11:02:25 am by Pete »

Offline gsseirik

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Re: C11G 54 no spark
« Reply #13 on: July 15, 2019, 06:43:55 am »
Thank you very much Faster!

Offline timsdad

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Re: C11G 54 no spark
« Reply #14 on: July 15, 2019, 08:22:32 am »
Yes, that is a basic wiring diagram for a 12 volt system. And I can now read Norwegian.

Ray
Just a motorcyclist.