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(Solved!) Had to get a jump start from roadside assistance; starter motor not cranking after a chilly night; intermitent issue?!


p6x
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On 11/18/2021 at 5:54 PM, docc said:

Just to clarify, there are two distinct "no start" scenarios with the V11: 1) slow crank followed by solenoid clicking/ or just solenoid clicking, and 2) no action at all when the starter button is pressed.

Case #1 is being discussed here, extensively, and can be multicausal. Case #2 will sometimes exhibit a sudden recovery as if nothing had happened. Sometimes this can be reproduced by holding in the starter button while rotating the bars lock-to-lock. If the starter suddenly engages with full force, the culprit is likely the bullet connectors for the clutch switch lock-out located on the left forward side of the frame spine beneath the tank.

DSCN1472.jpg

My work around, is to turn the switch to the "lock" position, thus turning all the way counter clockwise, and then try again. It has been successful so far.

If I don't depress the clutch lever, the dashboard lights don't dim. Circuit is not closed.

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18 hours ago, Kiwi_Roy said:

I don't know of any grease that actually conducts electricity, take your multimeter on Ohms and see, take a picture and post it here if you find a conductor.

Good question. I looked at the "Carbon Conductive" grease mentioned by P6x Carbon Conductive Grease (mgchemicals.com)

This "conductive grease" claims resistivity of 114Ω.cm. Since resistivity is the inverse of conductivity, then this is actually about as conductive as drinking water. (IE very poor)

So anyway, I measured the resistance of silver goop and C5A copper anti-seize. The resistance of both was too high for my meter to measure.

Non Conductive Grease.jpg

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27 minutes ago, MartyNZ said:

Good question. I looked at the "Carbon Conductive" grease mentioned by P6x Carbon Conductive Grease (mgchemicals.com)

This "conductive grease" claims resistivity of 114Ω.cm. Since resistivity is the inverse of conductivity, then this is actually about as conductive as drinking water. (IE very poor)

So anyway, I measured the resistance of silver goop and C5A copper anti-seize. The resistance of both was too high for my meter to measure.

Non Conductive Grease.jpg

I don't think a multi meter is really capable of measuring that kind of insulation.

We normally test our cable through 500 or 1000 Volts. Multi Meters use low voltage to test insulation. https://industrial-meters.com/products/cem-dt-6605-digital-insulation-tester-meg-giga-ohm-meter

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20 hours ago, Kiwi_Roy said:

I don't know of any grease that actually conducts electricity, take your multimeter on Ohms and see, take a picture and post it here if you find a conductor.

I did find a conductive resin (I know, too much junk lying about) and it was very conductive. The uncured "part A" measured at 2Ω over 10mm in a smear left in the lid. Nice, but I can't think of a use for it in my bike.

It does tell me that a conductive paste is possible, but it would be bad in an ignition switch.

Conductive adhesive.jpg

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On 11/18/2021 at 3:54 PM, docc said:

Just to clarify, there are two distinct "no start" scenarios with the V11: 1) slow crank followed by solenoid clicking/ or just solenoid clicking, and 2) no action at all when the starter button is pressed.

Case #1 is being discussed here, extensively, and can be multicausal. Case #2 will sometimes exhibit a sudden recovery as if nothing had happened. Sometimes this can be reproduced by holding in the starter button while rotating the bars lock-to-lock. If the starter suddenly engages with full force, the culprit is likely the bullet connectors for the clutch switch lock-out located on the left forward side of the frame spine beneath the tank.

DSCN1472.jpg

This is a very good explanation of the bullet connector problem, My 01 VII Sport would suffer occasionally but it never got so bad I had to fix it.

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On 11/16/2021 at 5:37 PM, p6x said:

I did not. But, the battery is brand new. This is one of the first consumable I replaced.

And when I crank the starter, it all sounds healthy. I feel that I would be able to identify a weak battery. One can always be wrong, of course. But the problem that many have experienced, and that I did too, seem to be related to what K-Boy described in multiple threads.

When the starter does not crank, there is absolutely zero solenoid noise. It is just like there is not load going through. You can hear the fuel pump, and when you turn the key, the dash board lights dim, but nothing happens. And if you insist, you blow the 15 Amps starter motor fuse.

This is because there is not enough current flowing through the coils probably 20 - 25 Amps. the solenoid is just sitting there, eventually it melts the 15 Amp fuse.

The coils are designed to draw over 50 Amps but going through the ignition switch even a clean one you will be lucky to get 30 Amps barely enough to encourage the solenoid to move.

The strength of an electromagnet is proportional to the number of turns x the current flow so at 20 Amps its only pulling at 40% of its design strength.

The dashboard lights dim because you are pulling a lot of current through the switch and the contact resistance is dropping the Voltage, if you clean the contacts you will find it improves.

After a few years the Vaseline in the switch gets hard and tends to hold the contacts apart, On a cold day it will be even worse because the vaseline is even harder. Clean the old vaseline out and replace it you will notice a vast improvement.

If you really want to fix it you need to provide a better source of 12 Volts to the start relay however with the later VIIs you can't just feed 12 Volts from the battery to the start relay as you can with most other Guzzi because the Normally closed 87A contact goes to the headlight.

There's another easy way and thats to add another relay with the contact between the large live terminal and the spade connector, The new relay coil is triggered by the original wire that went to the solenoid spade, you also need to ground the other coil connection. Now all your switch has to supply is about 150 milliamps, the solenoid will pull ~ 60 Amps and the starter will perform how it was designed to.

Notes:

A fuse is optional, it should be 20 Amps because you have doubled the solenoid current. Although the current is much higher the duration is much shorter so it doesn't have time to heat the fuse (typical 15 milliseconds at 50 Amps then it drops back to 10 Amps)

The starter designer never intended it to be installed the way Guzzi do it.

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On 11/20/2021 at 3:50 PM, MartyNZ said:

I did find a conductive resin (I know, too much junk lying about) and it was very conductive. The uncured "part A" measured at 2Ω over 10mm in a smear left in the lid. Nice, but I can't think of a use for it in my bike.

It does tell me that a conductive paste is possible, but it would be bad in an ignition switch.

Conductive adhesive.jpg

Marty, thanks for the research.

I did a really interesting experiment a while back with a mixture of Sulphuric acid and an organic known as Nitrobenzine. The two solutions were mixed in a beaker with lab stirring system so it was a homogeneous mix.

I started out with a 50:50 mix and kept increasing the acid ratio. All of a sudden the solution went from an insulator to a conductor. The process engineer I was working with explained that the solution flipped from drops of acid separated by an oil film to drops of oil separated by an acid film. I played around for a couple of days trying different combinations, the funny thing once it had flipped you had to decrease the concentration by about 20% before it would flip back.

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1 hour ago, Kiwi_Roy said:

I did a really interesting experiment a while back with a mixture of Sulphuric acid and an organic known as Nitrobenzine. The two solutions were mixed in a beaker with lab stirring system so it was a homogeneous mix.

Ha, reminds me of an experiment I did as a school kid. I thought the nitrobenzene was related to tri-nitro-toluene (TNT), so I mixed up a batch of nitrobenzene in the chemistry lab, and poured it into the fuel tank of the big old Dennis school lawn mower. I watched the mowing for a long time before I realized I wasn't going to see anything exciting. :unsure:

image.png

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I had a similar problem on my 2005 V11 but I didn't think about the possibility that the volts may be dropped across degraded contacts of the ignition switch that feeds the contacts of the starter mini-relay and through that the starter contactor coil.  So I'm definitely NOT saying that any of the previous conversation and ideas are wrong.  Quite the opposite. Putting a voltmeter on the input to the starter motor contactor would show whether this is the problem, especially if you know what the normal voltage drop should be.

My, hopefully positive, contribution to this thread is to say that my diagnosis was that there was a problem with the starter motor contactor whose contacts seemed to add sufficient resistance to make cranking poor or to stall.  It was never clear to me whether the mechanical contactor mechanism degraded and was getting partially seized so as to put less contact pressure on its starter contacts, or if it was simply that the starter contacts themselves had started to pit and degrade.  All I noticed was that the starter motor was very slow (or would fail to crank) but often would start OK on the second attempt.  My hypothesis was that this was either because the battery was a bit warmer and delivered a bit more current to the contactor coil or perhaps the main contactor contacts just closed with a bit less contact resistance that time.  I got a new starter and the problem was solved, so, in my case at least, I feel that the problem was a degradation in the motor contactor mechanism or contacts.  At 500A transient peak and 150A cranking, just the slightest extra contact resistance can be disastrous and with this d.c. current you might expect contactor deterioration over time.   But the possibility that the contactor coil does not get sufficient current to pull in the main motor contacts strongly would have exactly the same effect so worth bearing both in mind before investing in a new starter.

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2 hours ago, PeterT said:

I had a similar problem on my 2005 V11 but I didn't think about the possibility that the volts may be dropped across degraded contacts of the ignition switch that feeds the contacts --------

The earlier bikes took a direct feed from the battery to the start relay so the relay could feed the solenoid coils about 50 Amps. all the ignition switch carried was about 6 Amps.

I think about 2004 Guzzi changed the wiring to feed the start relay through the ignition switch so now the switch and wiring has to supply the solenoid coils, I doubt you will get more than 30 Amps on a good day, all kinds of Voltage drop through the switch and wiring.

Net result 30/50 or 60% of the magnetic field the solenoid was designed to supply, would you be happy if your Guzzi engine only put out 60%?

When the solenoid current drops a bit further through dirty contacts (around 25 Amps) the solenoid doesn't even try to move, eventually the 15 Amp fuse blows.

As soon as the solenoid main contacts close the coil current drops to just 10 Amps, it doesn't take much to hold the solenoid in place because the gap is small but it takes a super strong magnetic field to get it to start moving when the gap is large.

There are 2 coils in the solenoid

The holding coil 300 turns of fairly light wire drawing 10 Amps  3,000 Ampere Turns

The Grunt coil 300 turns of larger wire wound on next to the core so as well as being fatter its also much shorter drawing 40 or more Amps  12,000 Ampere Turns. (4 x as strong)

Ampere turns is the way of expressing the magnetic field strength 

The best way to prove it to yourself is start the bike a few times normally then take a wire and feed the solenoid directly by touching the wire direct to the battery, on your 2005 the solenoid will snap in at least 3 x faster.

BTW, a good battery will hold about 10 Volts while cranking but while the solenoid is stroking the Voltage should be over 12 because the contact is not yet closed.

I've tried every way I can think of to explain Startus Interuptus, I guess I will never make a good teacher lol

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That is likely the best explanation, ever. :thumbsup:

Pretty sure the V11 wiring changed in 2002 based upon those reporting results of the “Livin’ Easy Test” to see if Relay #1 is doing the heavy lifting like on the early V11.

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8 hours ago, docc said:

That is likely the best explanation, ever. :thumbsup:

Pretty sure the V11 wiring changed in 2002 based upon those reporting results of the “Livin’ Easy Test” to see if Relay #1 is doing the heavy lifting like on the early V11.

Yep, the Mighty Scura had startus interuptus. KR kindly walked me through a simple wiring change, and it's been fine ever since.

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  • p6x changed the title to (Solved!) Had to get a jump start from roadside assistance; starter motor not cranking after a chilly night; intermitent issue?!

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