Author Topic: A Good Startus Interuptus Fix  (Read 447 times)

Offline Kiwi_Roy

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A Good Startus Interuptus Fix
« on: August 16, 2018, 05:42:43 PM »
Recently I have been helping a Stelvio owner try to fix his starting issues.
John Henry posted how he did his.
His method might be more palatable for some owners than cutting the loom.
While I'm not a fan of adding extra relays knowing that the Start relay is right at the front of the Stelvio it makes sense in this case.



What I particularly like, it shortens the path for the current between battery and solenoid, this pretty much guarantees that the solenoid now works at least twice as fast as it did when the bike first rolled out of the factory.
Zoom Zoom  :thumb: :thumb:
« Last Edit: August 16, 2018, 05:43:33 PM by Kiwi_Roy »
72 Eldorado
07 Griso 2 Valve

Moto Guzzi - making electricians out of riders since 1921

Offline Chuck in Indiana

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Re: A Good Startus Interuptus Fix
« Reply #1 on: August 16, 2018, 05:50:11 PM »
Dang! He's not as dumb as he lets on..  :evil:  :whip2:  :grin:
Chuck in (Elwood) Indiana/sometimes SoCal

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Offline Phang

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Re: A Good Startus Interuptus Fix
« Reply #2 on: August 16, 2018, 06:52:44 PM »
I have this setup on my Griso using 10 AWG wire.

what I don't like is the relatively higher component/connection counts and it is only as reliable as the additional relay.

the mild OCD side of me managed to reduce two connections by using this little fused relay  :grin:

also, keep the additional relay/fuse easily accessible in case you need to pull the connectors/fuse when it stuck

2009 Griso 8V SE Tenni (Green)
2000 V11 Sport (Green)
1973 V7 Sport (Green)


Offline Rebochi

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Re: A Good Startus Interuptus Fix
« Reply #3 on: August 16, 2018, 07:27:34 PM »
    That is how I wired my 1200Sport. I used stuff that was sitting around the shop and works fine.
1200 GS
1200 Sport
1100 Griso
 V11  Lemans

Offline Kiwi_Roy

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Re: A Good Startus Interuptus Fix
« Reply #4 on: August 16, 2018, 11:40:14 PM »
Phang,
          That does look like a tidy solution, do you have a part No for the relay?
If you want it to be even more reliable make the trigger wire long enough to reach the battery +, I will post a pic of mine.
I have only seen one starter stick on, even pulling the trigger wire off wouldn't stop it, had to disconnect the battery.
I think it was you who told me the reason for the Startup Maintenance Relay was to maintain cranking even with a low battery.

Note: I don't like adding components, there's already two start relays but the ZZ solution shortened the trigger wire significantly and some will find it easier to understand.
No changes to the existing loom.

If Guzzi would get their act together none of this would be needed.
« Last Edit: August 16, 2018, 11:46:32 PM by Kiwi_Roy »
72 Eldorado
07 Griso 2 Valve

Moto Guzzi - making electricians out of riders since 1921

Offline Phang

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Re: A Good Startus Interuptus Fix
« Reply #5 on: August 17, 2018, 01:54:58 AM »
Roy, I don't like adding extra component to solve problem too, I prefer to KISS (Keep It Simple & Stupid).

my original intention was to take the thin stock trigger wire out of the equation by having an extra relay, it allows the use of thicker cable channeling thick fat current from battery to the starter solenoid.

the part number of the fused relay is HELLA 003530041

take note of the Type A terminal layout



2009 Griso 8V SE Tenni (Green)
2000 V11 Sport (Green)
1973 V7 Sport (Green)

Offline Kiwi_Roy

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Re: A Good Startus Interuptus Fix
« Reply #6 on: August 17, 2018, 08:42:33 AM »

my original intention was to take the thin stock trigger wire out of the equation

This is all I did on my 07 Griso, going up a couple of wire sizes reduced the solenoid operating time to 1/3 what it was.
I think Luigi measures the current draw, sees 10 Amps and wires it accordingly completely missing the high inrush current because it's so short.
72 Eldorado
07 Griso 2 Valve

Moto Guzzi - making electricians out of riders since 1921

Offline bigbikerrick

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Re: A Good Startus Interuptus Fix
« Reply #7 on: August 17, 2018, 12:15:03 PM »
So the wire that passes insufficient current for that very brief period, is the smaller wire that connects to the solenoid with the spade connector?
Sorry, if this is a stupid question, just want to make sure. Electrical stuff has always been a bit of a challenge for me to understand. :smiley:
Rick.
"You meet the coolest people on a Guzzi"

Offline Kiwi_Roy

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Re: A Good Startus Interuptus Fix
« Reply #8 on: August 17, 2018, 11:53:51 PM »
So the wire that passes insufficient current for that very brief period, is the smaller wire that connects to the solenoid with the spade connector?
Sorry, if this is a stupid question, just want to make sure. Electrical stuff has always been a bit of a challenge for me to understand. :smiley:
Rick.
Yes thats correct but on the bikes with the relay fed through the switch it's just as likely to be that.

This is what I found on the 07 Griso
I thought I would investigate the new to me 2007 GRiSO to see if it would benefit from the Startus Interuptus fix.
I was surprised to find the start relay fed direct from the battery, not through the ignition switch, this IMHO is how every Guzzi should be wired.
But on further examination I found the tiniest of wires from the relay to the solenoid. I knew it would benefit from a larger wire but thought I would document the improvement

I do this by measuring with an oscilloscope the peak current into the solenoid and the time it takes for this to drop down to the holding current

I measured this time and I find the solenoid pulse lasts for 50 milliseconds while the solenoid current peaks about 22 Amps which is ok but not great I suspect this is barely over the point Startus Interrupts takes over and the solenoid just sits there

So then I upgraded the wire from the relay to the solenoid. The current pulse now lasts only about 15 milliseconds, less than 1/3 as long telling me the solenoid is operating at three times the speed it was before and the current peaks just over 30 Amps. Eight Amps doesn't seem like a lot but 3 x as fast, you can't knock that.

Note: This current I am referring to is not the cranking current, it's just the current into the solenoid.

I have a storage scope but it's quicker just to sketch out the trace. I drew Before and After on top of each other for comparison.
You can see what a huge difference it made when I replaced Luigi's little bitty wire (Red Trace) with an 18 gauge wire (Green Trace)



Let me say again, this is not the starter motor current, it's just the current going to the solenoid coils.
It stands to reason a faster solenoid is less likely to hang up giving you the dreaded click.
« Last Edit: August 18, 2018, 12:24:44 AM by Kiwi_Roy »
72 Eldorado
07 Griso 2 Valve

Moto Guzzi - making electricians out of riders since 1921

Offline Phang

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Re: A Good Startus Interuptus Fix
« Reply #9 on: August 18, 2018, 12:03:01 AM »
Thanks for sharing Roy, that graph explained everything  :thumb:
2009 Griso 8V SE Tenni (Green)
2000 V11 Sport (Green)
1973 V7 Sport (Green)

Offline bigbikerrick

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Re: A Good Startus Interuptus Fix
« Reply #10 on: August 18, 2018, 11:47:34 AM »
Thank you, Roy, for the detailed explanation, and testing you did.
Excellent! :thumb:
Rick
"You meet the coolest people on a Guzzi"


 

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