confusing electricity on G5

Welcome to the next instalment of the ongoing G5 saga, having got the bike up and running and having used it every day this week i decided to give it a clean which at one stage involved “muck off” and a light sprinkling of water to wash it off, having dried it off and left it running for a while off i went to fill up with fuel.
Having done so i started the bike no problem and got about 10 feet when it cut out and would not restart, all instrument and lights working but no spark.
The problem is its been rewired and had electronic ign installed (Lucas AB11 Electronic Ignition Amplifier 47270 B ) and a modern fusebox by someone who knew what they were doing which is more than i do.
Where to start? no spark to the plugs, but everything else appears to be working.
Can someone talk me thro a step by step as to what to check please do i start at the plug leads and work back if so how?

Is there a kill switch on the side stand? One would have been fitted as standard. Is the kill switch on the handlebars on? I have drawn a coloured wiring diagram for the G5, send me a PM if you would like a copy.

Best of luck Chris

AB11 is a RITA ignition I think? I don’t think this has a fused feed from memory.
It would be useful to know whether you have power to the box or if there is another issue.
When mine stopped (on my first ride) it had power but one of the coils have shuffled round in its bracket and a terminal was touching the frame.

Fault-finding guide here:

I agree with the above, it sounds like a coil issue. If you have power elsewhere then check them first.

Had the front off the amplifier but there is no sign of water ingress, ive downloaded info from both AO servises and eurospares on Rita fault finding but i have only the vaguest grasp of what im doing and although both are in some detail im floundering.
Since the bike was running okay immediately after cleaning for a while i find it hard to believe that the gap in the pickup has suddenly changed so im discounting that, have tried spark plug against head and turning ign on and off as suggested with no spark showing.
they both say test the coils but the description as to how is difficult to understand, is there an easy way to follow a path from ignition switch forwards to see where the breakdown is? and an easy way to test coils?

Electrics are relatively straightforward in a confusing, logical way. :open_mouth:
You need to get someone to show you, after that it’s easy.

Bit like life then

Did you check the kill switch then?

I assume the engine is turning over when you try to start it?

Might be worth taking the seat and side panels off, trying to start and then see if you can see or hear any sparking anywhere, or smoke, or electrical smell while pressing the starter.

Then trace the connections back from the plug caps and make sure nothing is loose.

Pickup falling off might also be a possibility, if someone didn’t fix it properly.

As Somersetlemon said check the kill switches, they stop power to the coils. The one on the side stand is way out in the weather and road salt. Pull off the spade terminals and clean them up, If that doesn’t work short out the stand kill switch using a bit of wire between the white and black/white wires on the switch. If it works when shorted then the switch is faulty. The side stand kill switch could have an intermittent fault or could have failed when you went over a bump 10 feet up the road. You are lucky you only got that far and not 10 miles! :smiley:

The power to the coils comes from fuse F1 via a brown wire to the ignition key switch and then to the handlebar kill switch via a white wire from there it travels back to the side stand kill switch along another white wire and from there to the coils via a black/white wire.

Check all of those connection by pulling off the spades and cleaning the contacts, if they are loose pinch the spade with pliers to make a better contact. The power to the coils travels a long way around the bike and through two switches, many owners remove the kill switches especially the side stand one, then they have to remember not to leave it deployed when pulling away.

As I said before I have produced a coloured A3 wiring diagram for the G5 and if you want a free pdf copy send me your email address via PM.


Hi Chris
Thanks for your comments a wiring diagram would be helpful however parts of the wiring have been redone modern spade fuses etc and not necessarily in the original colour I think I need to trace back from the start button (modern) and try to find the problem if it’s coils it seems amazing they have both gone at the same time and surely if one had gone it would at least make an attempt to run on the other.
The engine was running sweet as a nut one minute and nothing the next.
When I examined the fuses there were two blown but when replaced no change and they stayed intact, at this stage I still have to establish what they protect.

Not sure if yours is the same, but my RITA has a pair of 6 volt coils in series. Both plugs fire at the same time, so one spark is wasted.
But could mean that a fault on one coil could kill both cylinders.
You should be able to tell by looking to see if there is a link wire from + on one coil to - on the other.

When my coils failed letting them cool down gave me a spark again and then failed once they got hot again. You can normally tell because the coil is hotter to the touch than normal if its gone. As a foot note, depending on your ignition system, when you leave the ignition on for too long without the bike running it can cook your coils. So when checking for faults, turn the key, check whatever your checking, then turn off as soon as you can.

The coils are not fed through the starter button, all the starter button does is earths the starter relay, so if you have no power to the coils it will not be the starter button. Trace the wires back from the coils. Black/white wire is the supply, it should lead back to the side stand switch (if it is still there, it is usual for it to be removed as they can be problematic) from there the supply is via a white wire that comes from the ignition switch ( it usually gets there through the handlebar kill switch)
Fuse blowing is usually a sign of the problem, and can be why the engine stops suddenly.

Fuse 1 - Power to ignition switch, horns, headlamp flash, stop lights
Fuse 2 - Starter, fuel tap
Fuse 3 - Lights
Fuse 6 - Parking lights
Fuse 5 - Aux lights
Fuse 6 - Indicators

Even if the bike has been rewired I doubt that the power to the coils will come from anywhere but the ignition switch, and the kill switches will (if they are still fitted) be between the ignition switch and the coils.

^ Yes.

Forget testing the coils, first you need to check if there is power to them. You will need a multi meter or a 12V bulb with two wires, connect one to the black/white wire feeding the coils and the other to an earth. If the bulb lights (with the ignition switched on) your coils are the problem, if it doesn’t light then it is the supply wiring as I have noted above. It is highly unlikely that both coils will fail on a standard set up, however as RR has said above, if you have a Rita electronic ignition system it is possible that one coil has failed.
I would suggest that you check if you have power to the coils first before testing anything else. My money is still on the kill switch :smiley:

My kill switch has the 2 wires soldered together, and there is no side stand switch.
I thought it was an unfused supply to the RITA box but without the wiring diagram I can’t be sure.

Leading a VMCC run last year we were caught in a deluge. As we slowed to a halt for a broken down rider, my 750 stopped dead. Everything worked, everything. Except the engine wouldn’t fire. We stood sheltering under trees for more than an hour, I tried my bike every so often but it wouldn’t go. Eventually the other guys got going, and finally after trying mine for the umpteenth time it miraculously started and ran fine. Got me home without a cough.
I came to the conclusion the very heavy rain combined with riding slowly had allowed a drop or two to penetrate the kill switch and stop the motor. I would hazard a guess that your problem is somewhere on the kill circuit.

It’s a Guzzi. It just got p—ed off with the rain and wanted a rest!