Author Topic: NGC Electrical help needed  (Read 485 times)

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
NGC Electrical help needed
« on: June 22, 2022, 02:14:01 PM »
I need help sourcing a rear brake light switch for the Gilera 106 SS, this is not a typical push or pull type brake switch

The brake light switch for this bike is interconnected to the stator ignition coil circuit, energy transfer ignition, no battery, 6V AC.

The stator coil for the ignition sends 6V AC power to the points / condenser / 6V coil from one end and the other end to the brake light stop switch. When the brake pedal is NOT pressed there is a rera brake switch connection to frame ground, this completes the ignition coil ground, when the brake pedal is pressed the brake switch ground connection is shunted and ground flows through the stop light to frame ground.

If the brake light bulb is burnt out the engine will die when the brake pedal is pressed.

The Sears parts manual lists the brake light switch as 45788. No idea if this a CEV or Aprilia unit, the stator is CEV.

I am told dome Ducati singles with energy transfer ignition (no battery) used the same system.

ant help much appreciated.

Jim
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Online Antietam Classic Cycle

  • Gaggle Hero
  • *****
  • *
  • Posts: 13166
  • Happily stuck in the past.
    • Antietam Classic Cycle
  • Location: Rohrersville, Maryland
Re: NGC Electrical help needed
« Reply #1 on: June 22, 2022, 03:28:03 PM »
Any idea of what the switch looks like?
Charlie

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #2 on: June 22, 2022, 04:55:06 PM »
Any idea of what the switch looks like?

from the Sears Gilera 106 SS parts manual - #20



This is what I had on the bike, its a simple spring loaded switch but no ground connection

48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Online AJ Huff

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 3842
  • Location: College Community IA
« Last Edit: June 22, 2022, 05:01:55 PM by AJ Huff »
'71 Ambassador
'01 California Special
'05 Road King
MGNOC# L-753

Wildgoose Chase Moto Guzzi

Re: NGC Electrical help needed
« Reply #3 on: June 22, 2022, 05:01:04 PM »

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #4 on: June 22, 2022, 05:13:58 PM »
Same as this?

https://www.ebay.com/itm/234573619151?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=FCBArDntTtm&sssrc=2349624&ssuid=W4Rosr9IQ7K&var=&widget_ver=artemis&media=COPY

If not, maybe contact that seller.

-AJ

As far as I can figure out this won;t work, I have one of these on a Benelli. I can't find any other wiring diagram for a bike that shows a ground symbol off the rear brake light switch. Now that my electrical tech friend explained to me how the ignition circuit works it kind of makes sense how Gilera (and some small Ducatis)wired the energy transfer ignition.

The coil on the right with the fine wires is the ignition coil and also the stop light coil, the left coil with the thicker wires is for headlight, tail light and horn. The left coil has one red wire coming out of it and the other end of the coil is grounded to the stator body.

The right hand coil has a green wire coming out one side for the stop light and a grey wire out the other end that goes to points / condenser and 6V coil, This coil is not grounded to the stator body and to complete the circuit there has to be a ground, hence the strange setup where the stop light switch forms the ground until the brake pedal is pressed and when the brake pedal is pressed ground winds its way through the brake light to frame ground.

This is why the owners manual warns that if the rear brake light is burnt out the bike will die when the brake pedal is pressed due to loss of ground.



We tested the switches I have to see if there is a ground circuit built into the body that is constant until the switch is depressed, nothing on the ones I have.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #5 on: June 22, 2022, 05:23:22 PM »
the electrical diagram

48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #6 on: June 22, 2022, 05:46:50 PM »
found a picture of the stock rear brake light switch

48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline Paul_Tim

  • New Egg
  • *
  • Posts: 14
Re: NGC Electrical help needed
« Reply #7 on: June 23, 2022, 04:12:47 AM »
Looks to me like the switch needs to have normally closed (NC) contacts with one terminal being grounded and the other having both the wire to the coil and the wire to the bulb connected to it.
In normal operation the current passes through the NC contacts directly to ground. When the brake is operated the contacts open and the current no longer flows through the switch but has to reach ground via the stop lamp bulb.
Don't think you need a switch with an integrated ground connection just the right contact type (NC or operate to open) and a link from one terminal to ground.

Don't you love obscure italian engines, it took me ages to understand the generator wiring on my Italjet.

Offline nc43bsa

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 1195
  • Location: Mooresville NC
Re: NGC Electrical help needed
« Reply #8 on: June 23, 2022, 09:50:22 AM »
What a bizarre way to wire a brake light.
1990 MilleGT

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #9 on: June 23, 2022, 10:05:16 AM »
Looks to me like the switch needs to have normally closed (NC) contacts with one terminal being grounded and the other having both the wire to the coil and the wire to the bulb connected to it.
In normal operation the current passes through the NC contacts directly to ground. When the brake is operated the contacts open and the current no longer flows through the switch but has to reach ground via the stop lamp bulb.
Don't think you need a switch with an integrated ground connection just the right contact type (NC or operate to open) and a link from one terminal to ground.

Don't you love obscure italian engines, it took me ages to understand the generator wiring on my Italjet.

Thanks for the explanation

I will give that a try. The green wire from Stator coil is sending the power to illuminate the stop lamp. The switch I have is normally open, press pedal and plunger extends completing circuit. Just talking my way through this. I donít understand how the grounded wire allows current to pass through the switch to tail lamp and not be a short circuit. Scratching head?
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Online AJ Huff

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 3842
  • Location: College Community IA
Re: NGC Electrical help needed
« Reply #10 on: June 23, 2022, 10:35:32 AM »
There's a brief thread from a few years ago, here. Not a lot of info but maybe a few hints could help.

https://wildguzzi.com/forum/index.php?topic=78497.0

-AJ
'71 Ambassador
'01 California Special
'05 Road King
MGNOC# L-753

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #11 on: June 23, 2022, 10:43:55 AM »
Thanks for the link, great info.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Online centauro

  • Gosling
  • ***
  • Posts: 420
  • Location: FL
Re: NGC Electrical help needed
« Reply #12 on: June 23, 2022, 02:17:02 PM »
What a bizarre way to wire a brake light.

This is the also the same way that vintage Vespas without batteries operate. The switch is normally closed (NC),and opens when actuated. As long as the rear brake light bulb and its wiring remain uninterrupted, the system works. If you can find a way to attach this Vespa switch below, it would work:

https://www.scootermercato.com/Scooter-Parts/Switches/55316

I consider this set up simply elegant and easy to troubleshoot. These wiring systems of that era had no voltage regulators; the voltage regulation was achieved by keeping a proper electrical load provided that all bulbs worked. Their total combined resistance provided the necessary regulation. We are only talking about a max of 30-35 watts produced by the stator coils.
Val Barone
1984 1000 SP/NT (sold)
1973 Benelli 650S Tornado (sold)
1985 Vespa PX150E
1973 Honda CB 350 Four

Learn from other's mistakes ; you won't live long enough to make them all yourself.  Eleanor Roosevelt

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #13 on: June 23, 2022, 03:36:35 PM »
This is the also the same way that vintage Vespas without batteries operate. The switch is normally closed (NC),and opens when actuated. As long as the rear brake light bulb and its wiring remain uninterrupted, the system works. If you can find a way to attach this Vespa switch below, it would work:

https://www.scootermercato.com/Scooter-Parts/Switches/55316

I consider this set up simply elegant and easy to troubleshoot. These wiring systems of that era had no voltage regulators; the voltage regulation was achieved by keeping a proper electrical load provided that all bulbs worked. Their total combined resistance provided the necessary regulation. We are only talking about a max of 30-35 watts produced by the stator coils.

Thanks

I have several of those type of brake switches, pretty common on Aermacchi

48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 1657
  • Location: Edmonton, Canada
Re: NGC Electrical help needed
« Reply #14 on: June 27, 2022, 06:42:14 PM »
I had the chance to photograph a rear brake light switch on a Sears Gilera 124 on the weekend



and I was able to trace the wire out of the stator to the switch, just one wire from stator to switch and one wire from switch to brake light. no sign of a separate ground wire to frame from the one green wire from stator.



I think I may have found one or two sources for the switch, fingers crossed this will work

On UK Ebay



https://www.ebay.com/itm/203069940079?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

another possibility



https://www.ebay.com/itm/143041301693?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline Don G

  • Gaggle Mentor
  • ****
  • Posts: 946
  • Location: Smiley, Saskatchewan Canada
Re: NGC Electrical help needed
« Reply #15 on: June 27, 2022, 07:43:38 PM »
I wonder if a brake switch from an early 70s snowmobile would be similar? DonG

 


Harper's Moto Guzzi : Go Ride , Break Parts, Call me!
Harper's Moto Guzzi. Where we still answer the phone, use the highest quality parts, and also do Transmission, rear drive, and carb rebuilds fast. Call us at 816.697.3411 and get your problems resolved.
http://www.harpermoto.com
Advertise Here