Q regarding replacing the solenoid feed wire

Hello all,
In an attempt to tackle my bikes very odd case of startus interruptus my next attempt will be replacing the wire that feeds the starter solenoid from the starter relay for a thicker one as advised to me.
Steps I have already undertaken are:

- testing the startermotor by connecting the solenoid directly to the battery 30 times. It cranked without fail.
- replacing the starter relay
- checking and cleaning the battery terminals & earth connection
- taking apart the starter, removing the old grease, cleaning it and regreasing the wheels
- taking apart the solenoid, cleaning it with cleaning alcohol and bending the ‘earth tangs’ to make better contact
- installing a MPH startus interruptus kit

After all this the situation has improved a lot, however it still does the “click no start” about once a day. The 15A fuse in the startus interruptus kit blows when this happen. With a 20A fuse it won’t blow, just clicks and doesn’t start. Pressing the start button again starts the bike normally.

I’ve now bought some thicker 12 gauge wire (2.06mm) to replace the wire that feeds the solenoid from the startrelay. I examined the wiring diagram and have the following questions:
In the diagram, the feed splits. One part goes to the starter relay, the other part to the “starter maintenance” relay. I have no idea what that relay does, however I’m assuming I can’t just remove the feed wire by disconnecting it from the starter relay and solenoid and then pulling it out, as it will still be attached to the maintenance relay somewhere (I have no idea where it splits)?
If so I suppose its best to simply disconnect the feed wire and tape off the ends, and then create a new connection with my new thicker wire that runs from the solenoid to the terminal that the starter relay is connected to. However now the maintenance relay will not be attached to the new feed wire. I’m assuming I need to split my new wire so it goes to the maintenance relay as well?

Also, I may be jumping the gun here but if this doesn’t fix the issue, any suggestions on where to look next?


Wiring scheme:
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What I would do, (and I'm ready to do when this happens) is to get 2~3 meters of 2,5mm^2 automotive wire (insulation resist to oil, grease, heat etc), or at least silicone wire, and connect it in paralel with the existing wire.

Its tricky to remove the wire connector from the relay socket, without damaging it - I cant find the trick - so I would (will) strip about 1cm of the insulation close to the relay, without cutting the wire, and connect there, the new wire to the existing, creating a new splice.

At the other end, at the solenoid, its easy, cut the old connector and crimp both new and existing wire, at a new connector.

I'll use tinned connetor (its not easy to get loose over time) for wires 2~5mm (14~10AWG)
Something like this :
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The same connector can be used to connect the wires near the relay - cutting off the flat part of the connector will leave the piece that is used to crimp the wires.

Note: to properly crimp the terminal (and the wire-to-wire connection) you'll need a plier - crimping tool for non-insulated open type connectors. Something like this

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Note the detail, for eatch connector size, has one curve at one jaw, double curves at the other, thats for non-insulated open type, those that have ONE cuvre at eatch jaw (for eatch size) are for closed type terminals (like a tube that the cable has to slip in), and will not work properly on non-insulated - the wire will probably be loose.

You'll have to practice a bit - get enough terminals and destroy the to get it right, before even lifting the saddle...

Last one: To insulate the new splice near the relay, (and whatever else) I use "self galvanizing tape" - google it. The glue of the normal insulating tape, commonly used by electricians, tends to either melt or dry up, leaving room for problems...

Thanks, very useful

Can you tell what size the wire from relay to solenoid is on your 8 Valve, it's very small on the earlier 4 Valve. I don't see any reason why they would change it - YES just do it as Petros says or simply replace the wimpy wire altogether.

On the 8 Valve you are probably losing most of the Voltage in the ignition switch, it's a stupid idea to run the solenoid through that. Every modern Guzzi since 2002 has suffered from this stupidity.
The solenoid on your starter would draw 40-50 Amps the instant you press start if it was wired correctly. it has two coils, one that draws 10 Amps, I call that the "holding coil" and another that should draw 40 Amps I call the "pull in coil". The 15 Amp fuse pops if it fails to pull the solenoid in, it just doesn't quite have enough power to get it moving but continues to draw a high current, I'm guessing 20-25 Amps, not enough to pull in but enough to pop the fuse.
Why does it crank sometimes and not others I hear you ask, because the ignition switch makes better contact sometimes, try flicking the switch a few times see if I'm not right. I have not had one of this style apart but I think you will find the grease inside has gone hard, that's typically what happened to the switches on earlier models. The proper grease to use in the switch is Petroleum Jelly aka Vaseline from the baby section of your pharmacy. NOT what's commonly known as Dielectric grease, I'm told that's the worst you can do.

What I don't understand is why the MPH relay fix is not working for you, it should be applying battery Voltage right to the solenoid relay with a new wire, perhaps it is still using that wimpy wire from the relays to the solenoid, check that the spade connector is nice and tight, smear some Vaseline on it to stop corrosion.

If you look at my posting about Startus Interuptus (GRiSO 1200) you will see just adding a larger wire made the solenoid work 3 x as fast

Note:
The 1200 GRiSO is wired direct from battery through fuse to relay to solenoid
The 8 valve is wired from battery to fuse to ignition switch to relay to solenoid


Here is a sketch of the starter wiring I did years ago, taken from a 2001 VII Sport that had the starter wired how it should be (not through the switch). Even when the ignition switch got so bad it would barely run it still cranked like a champ.
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Next Step
If it were my bike I would throw away that extra relay and wire the start relay direct. The yellow wire feeding the Start relay should come direct from the battery through just a fuse for safety, that's what the other CARC guys have been doing for ages.
Apparently the reason for the Start Maintenance relay is to bypass the low Voltage start interlock, as long as you hold your finger on the button it will try to crank, I suspect this is Luigi trying to do a work around instead of fixing it properly, the 2 valve doesn't have that extra relay.

Harping back to the ignition switch, if you get some Voltage drop there it also shows up at the ECU as a low battery so "Sorry, I don't feel like starting today"

My earlier post re the 1200 GRiSO
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A little Background
When I first got my VII Sport i would read about Startus Interrupts on the forum, just out of curiosity i wondered how much current the starter solenoid draws so I put my Ohmeter across the coil, almost a dead short, how can that be? On further investigation I found there are two coils inside so I took some careful measurements by a method electricians use to measure low resistance. 1.05 Ohms to ground and 0.25 Ohms to the output terminal which is essentially shorted to ground through the armature. Assuming 12 Volts that calculates as 11.4 and 48 Amps or total of 59.4 Amps
You will never measure that with an ammeter because the high current disappears in a few milliseconds I use an oscilloscope to read it and saw about 45 Amps. (the GRiSO is quite a bit less because it still has some drop in the wires)

Alright. Replaced the wire today. The original wire wasn't extremely flimsy, about gauge 16 or 17 if I were to guess, but my new one (gauge 12) has about twice as much copper. I managed to remove the original wire from the terminal which was a pita, isolated it on both sides but left it otherwise in place, then connected the new wire from solenoid directly to the relay.
I don't want to spoof it, but so far it started about 5 times in a row without issues and with the original 15A fuse back in place, so hopefully that did the trick. I immediately noticed it now starts much faster after pressing the start button compared to before.

I ignored the maintenance relay completely (didn't splice the new wire to it). I hope that won't give issues.

That's interesting, they must have increased the wire gauge then, I measured the resistance on mine about 0.045 Ohms, doesn't sound like much until you know how much current flows. But the speed you noticed.
I take it the maintenance relay is still tied to the start relay, it should only pass about 10 Amps so the original wire is ok.

When I look back through the old schematics I can see several occasions when Luigi made an attempt at fixing this curse, I don't think they realize what's causing the problem, show me one schematic that shows two coils in the solenoid.

Kiwi_Roy wrote:

That's interesting, they must have increased the wire gauge then, I measured the resistance on mine about 0.045 Ohms, doesn't sound like much until you know how much current flows. But the speed you noticed.
I take it the maintenance relay is still tied to the start relay, it should only pass about 10 Amps so the original wire is ok.

When I look back through the old schematics I can see several occasions when Luigi made an attempt at fixing this curse, I don't think they realize what's causing the problem, show me one schematic that shows two coils in the solenoid.

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WIP picture. Orange (cut) wire is the original one, black connected to the terminal (looks a bit odd due to the startus interruptus kit that is between that terminal & the starter relay) is the new wire.

The maintenance relay is now only partially connected, but despite this I could notice no adverse effects. If you look at the wiring diagram in my original post, the maintenance relay (3) is still connected to the starter relay through slot 5, but slot 2 & 3 are still connected to the original no longer used solenoid feed wire. Slot 1 is still connected to the right light switch.

If this is a bad idea and I should definitely make sure that the maintenance relay is connected to the starter relay through slot 2 & 3 I'd love to know it

After I done the battery direct to relay fix, I had no starting problems for a good while but then one day it blew the damn fuse again.

I stripped the starter and solenoid to clean everything and grease the gears (not the solenoid, just clean) and still blew the 15 amp fuse on the very odd occasion.

Popped in a 20 amp fuse and haven't had that problem since. May not be technically correct, but works. Hold on to the 20 amp fuse just in case

The orange wire is much larger than the one on my 07 4 valve, it's more in size like the small brown one you see behind.
The wire 2,3 from the maintenance relay should be connected to the black as well I think.
Fang explained to me that the maintenance relay was added so that the ECU couldn't drop out the starter if it thought the Voltage was a bit low, as long as you hold your finger on the button it overrides the ECU to keep it cranking, a pretty crude fix IMHO, wiring it back in just might give you an advantage one day when the battery is a bit low.

It could be argued that the MPH fix removed the need for the maintenance relay by removing the load from the ignition switch which caused the Voltage to sag in the first place. The load of the solenoid to the battery is quite insignificant but 40 Amps across a fraction of an Ohm (ignition switch and wires) will cause quite a Voltage drop.

I will send you a PM

Why does the fuse pop?
If you were to design the start circuit it would be reasonable to measure the current the solenoid draws and provide wire and a fuse accordingly. If any of you owners try this with your multimeter you will read about 10 Amps while the bike is cranking, so a 15 Amp fuse would be ok eh?
What you don't see because it happens so fast is the additional inrush current that did most of the grunt work in getting the solenoid to engage the gear and close the main contacts, this can be anything from 20 to 40 Amps on top of the 10 you see, knowing that you might consider a larger wire and possibly larger fuse to match.
If this additional current is a bit weak for example only 15 Amps the solenoid may not be strong enough to move the gear and close the main contacts so it sits there at 25 Amps (10 + 15) until the fuse melts.

I think the ECU will maintain the start signal for a second or two after you take your thumb off the start button until the engine fires or it times out so you can't just give it a quick jab. Those with more GRiSO exposure can confirm that.
I think its reasonable to increase to a 20 if it prevents blown fuses, this will still protect the wiring.

Its beneficial to get as much current into the solenoid as possible, it ensures the solenoid is strong enough (the strength of a solenoid is Amps x No of turns in the coil) and speeds up the action expending less energy (Amps x Time) which is what causes fuses to blow.

BTW, if anyone's interested I will tell you how to measure the inrush current but fuses may be harmed in the process.

Kiwi_Roy wrote:

Why does the fuse pop?
...
...
...... energy (Amps x Time) which is what causes fuses to blow.....
....

As the peak current should be about 50A for les than 0.1s , the circuit design is correct, the 15A fuse is the one to use, as it can handle those 50A for 0,18sec or about 65A for that time (0.1s). The 15A fuse will need more than 18A for long time to eventualy melt... Constant 20,2A will melt it after 10 minutes. If it melts during the coils transition 0,1sec, the current may have been 90A or more...(600% of rated)

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Since the issue is not at the design but at the poor quality/rating of the used contacts/wires using biger fuse doesn't feel right... It will allow more current to flow through parts that already can't handle correctly the existing current.

Plus, its never smart to give slack to safety devices. The one time that they will be actualy needed, they should operate correctly.

Petros, good explanation, cred given...

avgpetro wrote:

[
As the peak current should be about 50A for les than 0.1s , the circuit design is correct, the 15A fuse is the one to use, as it can handle those 50A for 0,18se..........

Since the issue is not at the design but at the poor quality/rating of the used contacts/wires using biger fuse doesn't feel right... It will allow more current to flow through parts that already can't handle correctly the existing current.

Plus, its never smart to give slack to safety devices. The one time that they will be actualy needed, they should operate correctly.

Yes the peak current is normally for a very short period, <50 mS typically, the shorter the better, when everything works the 15 Amp fuse is adequate.

If the circuit design is correct perhaps you could explain why owners are having so much trouble?
There IS a problem with the design!

Shouldn't the designer have specified good quality parts as part of the design?
Actually I don't agree that the parts are bad quality IMHO it's just that the designers didn't have all the information they needed to do it right. if they knew there was going to be 50 Amps running through the wires they probably would have chosen a larger gauge wire, larger fuse and perhaps chosen not to route it through the ignition switch. I wonder what the rating of the switch is?
If you look at any of the Guzzi schematics the designer doesn't seem to know there are two coils involved.
I still maintain the designer thinks he/she is designing a 10 Amp circuit. The tiny wire they put in my 2007 supports that.

The current will never be over 50-55 Amps, it's simple Ohms Law

As an electrician for 60 years I have no hesitation in suggesting 25% larger fuse if it will hold the circuit together long enough to get by without blowing, I believe I said,"I think its reasonable to increase to a 20 if it prevents blown fuses, this will still protect the wiring".
it's not safe to not have a starter when you are stalled in traffic either.

To quote you
"The one time that they will be actualy needed, they should operate correctly"
A 20 will still fuse long before the wire melts.


Cheers
Roy

I can see both points, though every electrician/mechanic I've spoken to told me I shouldn't when I told them I've been riding with a 20A fuse instead of 15A (none of them ride guzzi's though). I mentioned it in a topic on a dutch motorcycle forum and was essentially called an idiot for doing something so incredibly dangerous.

Anyhow I'd prefer to get the wiring fixed so everything works as intended over just increasing the fuse size, and it seems like I have done so succefully. Yay me. Will reconnect the maintenance relay later this week when I have time.

One tiny unrelated question, I didn't want to open a topic for it. I'm currently replacing my scratched exhaust system for a new one. After I removed the silencer this afternoon before I had to go to work, I noticed this small threaded hole in the back of the Carc. Is it supposed to be open like that? I'm assuming it does, but just in case

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I took a look at mine, it has the same empty tapped hole, i wonder if it was an earlier speed pickup?

Good to know, thank you!

Finished reconnecting the maintenance relay, soldered the connection so hopefully it will hold for a long time. All functionality is now restored (holding the start button now cranks the bike as well) and everything seems to work perfectly. No more blowing fuses.
I can recommend doing this to anyone who has issues with the bike not starting.

Can't thank you enough for suggesting replacing the solenoid feed wire in the first place Roy, I'd give you some grisoghetto cred but I don't think I can for some reason.

You can use a jewellers screwdriver to remove the connector from the relay plug and then use the removed wire as a switched live for acccessories or for turning on a PDM 60. This also allows for easy retro fixing should you need to.

BrianD wrote:

You can use a jewellers screwdriver to remove the connector from the relay plug and then use the removed wire as a switched live for acccessories or for turning on a PDM 60.  This also allows for easy retro fixing should you need to.

Maybe I'm misreading it, but wouldn't there only be current through that wire when you press the start button?

motor-timothy wrote:

BrianD wrote:

You can use a jewellers screwdriver to remove the connector from the relay plug and then use the removed wire as a switched live for acccessories or for turning on a PDM 60.  This also allows for easy retro fixing should you need to.

Maybe I'm misreading it, but wouldn't there only be current through that wire when you press the start button?

That's correct but lots of it, over 40 Amps the instant you press the button, then drops back to ~10

The thing an electro-magnet is only as strong as the current flowing through the coils, if you strangle it by using too small a wire or going up to the ignition switch and back it's only a fraction of what it should be.