Startus Inturuptus Question

I'm looking at doing the Startus Inturuptus fix on my 2012 8V GRiSO and would like confirmation on the wiring colours on the starting relay.

Power from battery - connect to Position 2 on relay Yellow wire ????
Wire from relay to starter solenoid - Position 5 on relay Orange/Yellow wire ???

The bike hasn't actually failed to start but often hesitates a second or two before the starter kicks in.
Quite often the dash goes blank during this hesitation.

Thanks.

in my last remaining brain cell, I recall that the 8V didn't suffer from startus interruptus.

On the earlier CARC bikes, the trick was to remove the yellow wire coming from the key switch to fuse B (2), and add a stout wire from fuse B directly to the battery positive.

But you have correctly selected the two wires that might make a difference if you want to go ahead with the mod.

How good is your battery (and the connections)?  That could contribute to the dash momentarily blanking out.

The connections are good, but I intend to go over them and check. The battery is good, but it is not a standard battery and it may be causing the issues or contributing to them.
The battery is a lithium battery, it was on the bike when I bought it. When I had the bike rollerised, must be a couple of year now the shop allowed it to discharge completely (the job took so long) and the battery did not recover so they replaced it with a new one. The bike had the same starting issues with both batteries.
I figured splicing in a couple of extra wires and a fuse is a pretty simple and easy job. The only tricky bit for me was correctly identifying the wires on my model.
On the you tube video I watched I thought the power wire was red and the feed to the solenoid was yellow. I'll have to have another look, anyway that's different from the diagram I got off this forum, probably posted by you

I suggest you try these wiring diagrams which are more accurate. Although not in colour, they have to ability to be able to highlight various functions to show which part of the wiring is being used.

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I use Adobe Acrobat reader to view the files. The layers are enabled by clicking on the layers icon on the LHS.

Brilliant wiring diagrams Kiwi Dave - thanks

Startus Interruptus affect nearly all Guzzis for the last 50 years and maybe longer. Some never, a lot do need some treatment.

Thanks for the wiring diagrams Dave.
The one for the 1200 8v is spot on for my bike, takes the guess work out.
The only diagram I had prior to this was a bit different in the starting relay area.

OK. Did the fix a couple of days ago.

A couple of observations. The wire I used to replace both the power feed and the trip wire to the solenoid was 2.68 mm2. It did not appear to be much larger than the existing wires.
Once you cut the wires by the relay you don't have much wire to play with just makes it a bit difficult to solder the wires.

On the first push of the starter button heard the relay and solenoid click, dash went blank but no cranking. After four or five attempts the bike finally started. After that, started first go for the next six or so starts.
The next day I put the battery on a charger. When it indicated a fully charged battery, disconnected and pushed the starter. Fired up and idled straight away.
The following day went for a start, no go. Pushed the starter and held the button in for a few seconds (2-3?). The relay and solenoid click straight away and the dash goes blank, eventually the starter slowly cranks and the bike runs.
Going to play around with it a bit today.

The battery is a SSB Lithium Prismatic cell battery 290 CCA and indicates 13.1 volts on the dash. Although it's only two years old I'm starting the suspect it may be the culprit all along.

Any thoughts on testing to see if the battery is at fault before I just go out and buy a replacement.

I've always shied away from Lithium batteries, they have a reputation for failing when the ambient temperature is low. One of the fixes is to turn the headlight to warm the battery up, but most modern bikes that is not possible until the motor is running. A classic Catch-22.

Others will disagree, but no lithiums for me.

Yes I'm done with Lithium batteries as well.
The bike wouldn't start at all this morning even though the battery was indicating 13.1 v, must have tried a dozen times.
Put it on charge for 20 min, was indicating 75% charge from the beginning got up to 13.4 v still 75% charged. Bike started first time at least half a dozen times after that.
Ordered a new battery.

The symptoms of Startus Interuptus and a Bad battery are very similar
The earlier 4 valve GRiSO was better wired than the later 8 Valve IMHO
Earlier 4  Valve 1100
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Trace the wire from the start relay terminal 3 you will see it originates at fuse C which is always alive
This is basically the same as you wire the later bikes when you add a kit
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Later 8 Valve 1200
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Here the yellow wire feeding the start relay terminal 3 originates at fuse F2 which is fed via the ignition switch (13)
Remember when you press Start and the relay closes the relay tries to send 50 Amps to the starter solenoid, in reality its lucky to get 30
I keep rabbiting on telling the owners to watch the number plate light or the park light in the headlight, they are both also fed by the weak yellow wire.
At the instant you press start the lamp will go dim indicating the low Voltage on yellow.
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The problem is if you have a weak battery or bad main ground it will also give you low Voltage so you need to sort out which it is, the simplest way to do that is hot wire the solenoid trigger wire, that will bypass the weak wiring and the starter should crank. Do this without turning the key On so it doesn't start and you can give it a good workout.
Warning: Make sure the bike is in Neutral and pull the clutch in for good measure. it will be self explanatory if you don't.
Take your multimeter on Voltage and fix the negative lead under a handy screw.
Jamb the positive lead into the battery Positive terminal while you make it crank, it should be able to hold 10 Volts.
Finally jamb the positive lead into the Negative terminal while you make it crank, it should stay close to zero, indicating Negative indicates a bad ground.

I would encourage you to watch this Video, its a bit long but a good one
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I'm on my 4th GRiSO... an 07, 09, 13 and 17.
The 09 and 13 are gone but none of them were in need of the fix.
My 07, which is the one that is most prone to that disease, is reliable as an anvil with 35.000 miles.
Guess I'm lucky...

Interesting that bad ground/earth connections and tortuously long power wire runs are still a Guzz characteristic 44 (?) years after the T3- pity they aren't a positive one
I used to find poor earthing from the battery both the easiest to check and the most effective mend. Any extra resistance in the battery earth line doesn't just reduce voltage and hence current out (especially starting); it is also resistance to the charge able to get back in between starts

Huge thanks to you Kiwi Roy.
Fortunately the battery I had ordered, before I saw your last post was out of stock, so I was able to cancel it.
I had another look at the bike, got out the multi meter and conducted your simple easy to follow procedure for testing battery and the ground.
Battery voltage held above 10 v while cranking with the starter solenoid hot wired to the battery.
The next step, however showed a very negative figure.

Undid the earth wire at the starter. It looked very clean but I gave all the connectors there a brush up with sand paper and re- assembled. The earth test then showed zero.
Did at least six actual starts on the button. All looks good now.

Thanks again.

Looks like I jumped the gun, thinking my issues were solved.
After cleaning up the earth the starting issues re- appeared a couple of days later.
Took 9 start attempts before it started. The relay and solenoid clicked but no attempt to crank.
The dash went blank but came back in a few seconds. Voltage was 13.2 but dropped somewhere below 10 v ( too fast to see the voltage) on the multi meter when attempting to start.
On the ninth attempt the bike started and then subsequently started six times first press of the starter after that.
I've installed a new battery and have had no issues since.
I've done three rides and at least a dozen starts.

I have a 2014 and the “startus” happened about a year after getting the bike new. When it wouldn’t start, it wouldn’t start no matter how many tries. I installed the MPH (Houston) kit and it’s been fine ever since except for a blown 15 amp fuse in the kit which I changed to a 20 amp after advice received here.

JohnA wrote:

I have a 2014 and the “startus” happened about a year after getting the bike new. When it wouldn’t start, it wouldn’t start no matter how many tries. I installed the MPH (Houston) kit and it’s been fine ever since except for a blown 15 amp fuse in the kit which I changed to a 20 amp after advice received here.

Guzzi have been screwing up the starter wiring for the last 40 years, don't expect them to fix it any time soon.
The solenoid would draw 50 Amps for a split second if it was wired right, just while pulling the gear into mesh, once the main contact closes the solenoid current drops to 10 Amps (holding current)
When you add an MPH kit or do your own simple fix you increase the solenoid current from about 25 to 35 Amps so you need to use a 20 Amp fuse.
If you also increase the size off the wire from the start relay to the solenoid you will get over 40 Amps.
You might think this would increase the stress on the fuse but not so because the higher current reduces the time it takes to engage the starter gear and drop to 10 Amps
I measured the engagement time on my 2 Valve GRiSO, it dropped from 50 to 15 milliseconds with a fatter wire, I think I used 18 gauge which is what I had handy.
Note: The early 2 Valve GRiSO 1100 was wired with a direct feed to the start relay, not like the later 1200 wired through the ignition switch
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I have come to the conclusion that the Guzzi engineers must have measured the solenoid current with a digital meter, missed the heavy inrush current and seen only the 10 Amp holding current and so chose fuse and wire size accordingly.
If they had bothered to measure the resistance of the spade connecter to chassis it would have caused them to wonder why the resistance was so low. Ohms Law actually applies to Guzzi's
Here is a sketch I did many years ago when I wondered what this "Startus Interuptus" was all about and took the trouble to make a few measurements.
I'm just a simple sparky that barely scraped through school if I can figure it out why can't a university trained engineer?
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Roy,
The mystery to me is why does it only happen to some bikes and not others (of even the same year) and why did it take a year to manifest itself on my bike?

JohnA wrote:

Roy,
The mystery to me is why does it only happen to some bikes and not others (of even the same year) and why did it take a year to manifest itself on my bike?

I was first familiar with with the 2000 era bikes, with those the problem was usually down to the contact in the ignition switch, when new the contact was good but after a few years the grease starts to go hard and hold the contacts apart.
If you pull the switch apart and re-fresh the grease with Vaseline it usually improved things for a while.
I tried to find the current rating of the ignition switch contacts but couldn't, but for sure its not 50 Amps
BTW the relays have a very high inrush rating, 100 Amps or more.
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The 2000 era bikes had the ignition switch mounted on the moving part with a wimpy set of wires,
At least the GRiSO has the switch on the main frame so the wiring is more direct.
When you install an MPH kit or roll your own most of the load is moved directly to the relay where it belongs, thats what relays do best.

But dont forget the wimpy wire from the start relay to the solenoid, it needs to be one or two sizes larger to pass 40+ Amps along to the solenoid.
I went up to a #18 on my GRiSO and it cut the solenoid engagement time from 50 to 15 milliseconds.
Make sure that the spade connector is nice and tight, thats a weak point.

A 20 Amp fuse is appropriate for the revised wiring.

JohnA wrote:

Roy,
The mystery to me is why does it only happen to some bikes and not others (of even the same year) and why did it take a year to manifest itself on my bike?

It could be something to do with the riding pattern, or climate who knows.
I do know for sure its a bad design, it's like they never learnt a thing in 40 years.

I understand that the 'flick in' relay that MG use has always had this current surge problem. But I am struggling with the interraction betwen (2) the Start up Relay and (3) the Start-up Maintenance Relay?

I am planning to run a 27.5amp, 3mm sq. wire from terminal 5 on relay (2) to the starter motor relay.
is that right?
...and would there be an advantage in running a fused 3mm sq wire from battery + to terminal 3 on relay (2)?

I have a theory that the startup maintenance relay was added because the Start relay was being turned off by the ECU due to low Voltage, the maintenance relay stays in as long as you hold your finger on the button. I have suggested several times that you could unplug the maintenance relay once you have replaced the weak yellow feed to the start relay with a direct feed from the battery. So far as I know no-ones tried it. (I only have a 2 Valve with better wiring)
If you watch the park light in the headlight while you start the bike it will tell you a story.
Key On - Park light comes On
Press Start - Park light will go dim for a split second or longer if the starter doesn't engage indicating low Voltage while both coils are drawing power.
While cranking - the light will go brighter again because now only the holding coil is drawing current ~ 10 Amps.
The earlier 4 Valve motor didn't have this extra relay but it had a direct feed to the Start relay.

When your dash goes blank thats because the Voltage has dipped right down, I doubt that this is caused by the battery as the solenoid is only pulling about 30 Amps at this stage, its more likely to be a bad connection or too much resistance in the ignition switch, watch the park light or maybe have someone watch the number plate light, its on the weak yellow feed too.

As to the main ground behind the starter, even though it looks clean it may have a layer of oxidization, file it clean and then apply some grease to the metal, that will keep the nasty Oxygen away. I use Vaseline for any joints around the bike, battery terminals. crimp links, crimp lugs all get a taste of Vaseline to stop the copper oxidizing.

Startus Fix
Snip the yellow wire below the relays, crimp or solder another yellow wire to it and feed it from the battery through a 20 Amp on-line fuse.
Snip the Orange/yellow wire below the relays and join it to a wire at least one size larger and run that to the solenoid spade connector, make sure the spade connector is nice and tight.

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If you are not sure where to cut these wires look at the diagram, cut them where they go from vertical to horizontal below the two relays, that way both relays will still be in circuit. Bear in mind I have never actually worked on an 8V GRiSO but I assume the wires between relays join close by. Tape up the other yellow because its still alive.

Thanks Roy - I agree that the Guzzi use of the word "maintenance" is a clue that the previous system was broke/joke!

I recall that when the factory rushed out a fix they titled the sheet "It has been foreseen in production......."
Of course we only wished that it had been "foreseen"!!

I was confused by the way that the unswitched power is fed to different sides of the relayed circuit - but i suppose polarity on that side is not an issue and it probably looked prettier on the loom-dolly in the factory

I have never seen a Guzzi drawing that shows the starter solenoid correctly, at the most they show just the holding coil that draws 10 Amps, a 15 Amp fuse is appropriate for that current.
The coil that does most of the Hard work I call the "Grunt Coil" is never shown, it will draw 45 - 50 Amps if its wired right and the magnetic strength of this coil is 4x that of the weak holding coil.
As you know sometimes the 15 Amp fuse blows, really a 20 Amp fuse is required, strangely the more current you get the less heating effect on the fuse because it operates for a much shorter time.

BTW the strength of a magnetic coil is a product of the amperage and the number of turns (Ampere Turns), both coils in this case have roughly 300 turns but the Grunt coil is wound using thicker wire and its much shorter because its wound on first, thats why its 4x as strong. The holding coil is wound over the top so its much longer as the radius increases and its thiner wire of course.

No these simple relays don't care about polarity, some relays do, the Main Injection Relay for example will only pick up if the polarity on the coil is correct.it has a diode in series with the coil to prevent it closing if the battery is accidentally put in backwards.
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