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Discussion Starter #1
I decided to create this thread because of the number of people with burned out ignition switches just lately. A new OEM ignition switch is quite a costly item, and most of these switches can be saved. This solution is very cheap and permanent. There are those who will decide to go hands free or keyless, but that is another subject and this thread is not aimed at those people.

The problem is usually caused by arcing and spark erosion inside the switch, often aided by moisture ingress. The solution is to take the elecrical load off the switch and replace the actual ignition switching with relays to eliminate arcing. The OEM switch then only has to provide the security side of things with the key.

Inside the ignition switch are 3 pairs of contacts which are, in effect, 3 separate switches. Each one of these internal 'switches' joins a pair of wires, so there are 6 wires on the switch. All 3 of the switches are switched on or off simultaneously when the key is turned. When the switch goes bad, from what I have seen over the past few years, it is usually just one, or perhaps two, pairs of contacts which are affected beyond repair. By using only one of the good pairs of contacts, the ignition switch can be repurposed to activate/deactivate the relays. Doing this has advantages:


  • It is a very cheap solution, for those who find the cost eye watering.
  • It is permanent.
  • The load on the switch is near zero, so no spark erosion of the contacts.
  • Nothing needs to be relocated.
  • This method can be used as a preventative measure, regardless of the switch still being good.
  • Should anything go wrong with the relays, they are very cheap to replace from any auto store.
As stated there are 6 wires on the switch itself. On models with the electronic speedo there are only 4 wires in the bike harness, but the switch is the same. It is just that one pair of internal contacts have been left unused. It still has 6 wires.

These are the wiring colours of the 6 wires on the switch, divided up into pairs. The numbers in the lists are the pin numbers of the connector block:

Carbed Bikes and EFI bikes with electronic speedo
1,2 White and Brown
3,4 Orange and Red/White
5,6 Red/Yellow and Green

EFI bikes with cable driven speedo
1,2 Blue and Red
3,4 White/Black and White/Green
5,6 Yellow and Brown

Below is the connection diagram covering all models. I have decided to use negative switching for the ignition switch, it does not matter which wire from the ignition switch is grounded, it can be joined with the ground wire to the front parking bulb or any convenient ground wire. Do not ground to the frame.

 

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Discussion Starter #5
A video would be nice. this is amazing!! thanks
Thank you for the compliment Vitesse.

Unfortunately I have no equpiment to make a video and I would have documented the process with pictures, but I do not have a bike to work on. My own has already been fitted with hands free keyless ignition and the wiring is different. If anyone does this and makes a video or has pictures it would be great if they would post them here. Meanwhile, a visual aid is all I have to offer right now.

 

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Great drawing Ripper..

I'm going to give this ago this week, one question..

I have 2 spare 5 pin relays (like the ones used for the starter relay)

Are they ok to use?

I'm guessing they are but obviously only connect the 4 pins we need.

thanks.
 

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Discussion Starter #7
Yes just leave pin 87a disconnected.
 

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Thank you for the compliment Vitesse.

Unfortunately I have no equpiment to make a video and I would have documented the process with pictures, but I do not have a bike to work on. My own has already been fitted with hands free keyless ignition and the wiring is different. If anyone does this and makes a video or has pictures it would be great if they would post them here. Meanwhile, a visual aid is all I have to offer right now.

What about one with the electonic speedo? Thanks
 

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Discussion Starter #9

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Great post Ripper. I hope i'll never need it though
 

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Discussion Starter #12
Great post Ripper. I hope i'll never need it though
Thanks steven, I hope that no one ever needs it, but it's there, as another option at least. I know that a few have replaced the switch a couple of times before finally giving up on it and going to the M-Lock or similar. The OEM switch is a fairly expensive item, even when bought used from fleabay, and of course you don't know what you are getting. The idea behind this is, even if you have bought a brand new switch, to prevent the same thing happening all over again. Or you can do it as a preemptive 'mod' to extend the life of a good switch for just the cost of a couple of relays and some connectors.
 

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Ripper,

Thanks for this, I followed your instructions and my bike now starts first time, every time.

Doing this has save me £150+ on buying a new Ignition switch so thank you.
 

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Discussion Starter #14
Thanks for the feedback Wayne, its good to know my thread has helped someone already.
 

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Discussion Starter #15
I have recieved some pictures from bonnie wayne, which with a little editing I have made a rough 'how to'. Many thanks for the photos Wayne.:smile2:

The ignition switch. How it happens and choosing a good pair of contacts...



The switch connector block...



The relay and switch interwiring...



And the finished product...

 

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This is how I would do it: A lot less re-wiring of the switch required and you only need just one relay
(which should be the case if it is that one pole that is consistently being damage, as per the image posted above)



Note that in any of the mods listed above as well as this one, you will lose the capability to use the Park Position of the key-switch.
It might be possible to keep it operational, but only if the Red/White pole of the switch is undamaged.

Note that in the schematic above I have assumed (perhaps incorrectly!) that the 'bad' junction is the Red/White to Orange pole;
if that bottom circuit that gets fried with the water is actually the Red/Yellow to Green Pole, just swap those wires respectively to the relay
(the Orange would then be the one that would have to connect to 86 of the Relay.)

In the following instruction, the colour in parentheses is the alternative, depending on which pole is damaged;
1. Cut the two wires off the damaged pole Red/White (Red/Yellow) and Orange (Green) at the switch itself
2. Pull these two wires wires from the Switch harness sleeving and connect to a relay
Red/White (Red/Yellow) to 30 and Orange (Green) to 87
3. Connect a small gauge wire to the Green (Orange) wire and connect to 86 of the Relay
4. Connect a ground wire (splice to the park lamp ground for example) to the 85 terminal of the Relay
5. At the Connector, cut the Brown and Silver/Grey wires about 2" from the connector and splice these together.

That should do it!

(Here is the diagram if it is the Red/Yellow - Green Pole that is damaged)

 

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decosse said:
A lot less re-wiring of the switch required and you only need just one relay
A slightly cheaper solution with less wiring agreed, but by using one of the switch poles that is not damaged you are still pulling the current through that pole, and normally with electrical contacts the using of current through them is were the pitting and burning occurs especially if it's not a solid contact for whatever reason , the switching negative of relays coils will use significantly less current and possibly negate the pole becoming burnt, you could also switch the +12v to the relays coils with the same effect.

If your needing to faff with your ignition for burnt poles you might as well sod the thing off completely,keyless, using 2 relays your only an rfid device away

based in the electrical industry, not automotive I will add, switches only ever control relays, which are the components that handle current
 

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... by using one of the switch poles that is not damaged you are still pulling the current through that pole ...
Yeah? So what - you means same as stock and continuing to utilize a pole which is operating just fine?
The point of this exercise was a REPAIR and my offering was the SIMPLEST way to achieve that repair; Yes, you can add multiple relays, or even an RFID device instead of the key, but that was not within the scope of what was simply a repair to overcome the common failure illustrated which is NOT caused by current, but by water ingress.
The current on any of these poles on a Carb Twin is fairly low anyway (single headlight, no fuel pump, no major ancillaries drain) so less benefit than for example an EFI Speed Triple or Rocket3 (that is switching about 15A through a single pole) - on those I would certainly advocate for a pro-active solution to bypass the switch and indeed I provide kits for those (both RFID and simply bypass). For the Twins, as far as REPAIR goes, my suggestion will suffice.
But sure Key-Less is a nice feature - for those who want that and can eliminate the key-switch completely. In my KeyLess system design, it doesn't even add any external switches at all and the OEM switch it uses to trigger only draws <1mA of current vs 140 mA for a Relay Coil.

Oh - and relays never fail, right? :D
 

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Man that is so cool that I could eliminate the key altogether and just hide a rocker switch somewhere to fire it up. Yes I understand the theft part. Or get one of those RFID things. Nice write up all.
 

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Discussion Starter #20
The point of this exercise was a REPAIR
No, DEcosse, the point of YOUR excersise is repair. The point of MY excersise, as the thread creator, was not only repair, but also relieving the switch of as much load as I possibly could.

simply a repair to overcome the common failure illustrated which is NOT caused by current, but by water ingress.
It is caused by both, water/moisture ingress causes oxidisation which leads to spark erosion, loss of contact and burning. My attempt, though not as simple as yours was to address both issues and lessen the chances of the switch failing again in the future. Personally I don't give a rat's ass if it takes an extra relay.

The current on any of these poles on a Carb Twin is fairly low anyway
And your point is?

The bottom line is that its enough to cause switch failure when coupled with moisture. Its not always the same pair/pairs of contacts that fail and I've known all three pairs to be iffy.

For the Twins, as far as REPAIR goes, my suggestion will suffice.
Yes it will, as far as a REPAIR goes. However I have to agree with Ade here.

In my KeyLess system design, it doesn't even add any external switches at all and the OEM switch it uses to trigger only draws <1mA of current vs 140 mA for a Relay Coil.
I wondered when we were going to get another advert...
 
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