Final Startus solution?

Tvboy,
Windshield is a Parabellum Scout. You can google that. It cost $600 unpainted and $800 painted. That’s a turnoff for many. It provides a lot of protection and you can get many different screen heights. They are interchangeable. Mine has an 8” now but it came with a 10”. The taller the uglier in my opinion. I think they will let you try one out (unpainted) nd return it if you don’t like it.

Thanks for that. I've never heard of that brand.
Fairings are a funny thing.
I consider them important to comfort at high speed but if they're ugly then no.

That is a bit spendy for me but I'll certainly take a look.

I'll bet it keeps a lot of 'southern bugs' off you. ha

melonman wrote:

Hi all
Just found a blown fuse under the seat
Replaced it took bike out all seems ok
Wonder if i shorted it doing the starter mod
Thanks for all the help
Hoping its sorted

That's probably all that happened so easy to do without noticing.
For the record what did you do to cure the starting?

Well, I just checked my solenoid and it has an internal resistance of .9-1.0 ohms.
That translates into a current draw more than 13 amps.
It sounds like my 15 amp starter fuse is barely above water.
I think I'll be making the mod very soon.
Thanks to Kiwi Roy and others for the history on this issue.

[quote="tvboy"]Well, I just checked my solenoid and it has an internal resistance of .9-1.0  ohms.
quote]

I think you will find it a lot less than that, try it again from the spade connector to a nice shiny starter bolt
Leave it in the bike for the test.
Put both meter leads on ground, say one on each starter bolt and subtract that reading from the first reading.

You probably found it very hard to to get a stable reading with your meter, it's right at the low end of the scale where it's not very accurate and the meter leads alone are probably around 0.2 Ohms.
I measured with my Fluke and it gave me somewhere between 0.2 and 0.4 Ohms, not very good eh?
Electricians use what's known as a drop test for measuring low resistance like this, they pass a relatively high known current through the unknown resistance then measure the voltage drop across it. Its possible to measure joints down to a millionth of an Ohm this way.

So I passed 2 Amps through the coils using my bench power supply and then measured the Voltage from the spade connector to chassis this gave me a Voltage of 0.503 Volts, easily done with even a cheap meter. Then by Ohms Law I was able to calculate  0.503 / 2 = 0.2515 Ohms (to 4 decimal places, very accurately)

So in theory the solenoid on my GRiSO will draw 12 / 0.2515 = 47.7 Amps at 12 Volts, thats quite achievable when you consider the battery could easily be at 14 Volts

Just suppose it only gets 6 Volts to the solenoid, it will only draw 23.8 Amps, this is about what it drew before I put a larger wire between the relay and the solenoid, barely enough to make it work.
So I think you will agree it's critical to eliminate as much resistance as possible.

Hi all, unsure if it is related but here goes.

Many months ago I had the dreaded startus interuptus strike GRiSO. I followed Dr Ropers advice and installed a 20 amp fuse which imporved the situation. Over time I noted that while the bike pretty much starts reliably, it is not without a small issue.

When I press the starter button the bike will ether start immeadiately, hesitate then start sfter a second or two (while this happens the screen appears to reset as if just turned on) or the solenoid clicks then I have to release the button and the bike starts second go.

Any ideas would be appreciated, I mentioned this to John at Motocicclo when the bike was being serviced but of course the bike started every time first go for him.

The screen resetting tells me you are losing Voltage across the ignition switch, the solenoid is sucking down the Voltage until the screen doesn't have enough and drops out, it's probably screwing with the ECU and robbing the motor of spark as well.
Once the solenoid finally closes things improve because the current drawn by the solenoid drops down i'm guessing from the low 20s to < 10 Amps so there's more left for the screen and it re-boots.

Do a little test
Take a few feet of No 18 wire and put a spade connector on one end, plug it onto the solenoid.
Make sure the bike is in Neutral, pull in the clutch for good measure and touch the other end of the wire briefly on battery Positive, that's how it should crank, every time.
(You don't need the key turned on unless you really want to start of course)


Note:
       Of course it's also possible your battery is shot or you have dirty terminals
The test I outlined will prove that one way or another.

Hi Kiwi_Roy,
I did exactly what you described.

The spade terminal was clean, the starter mounting bolts are clean.

I used different ground points around the bike. The mounting bolts gave the lowest reading as one would expect.
Apparently my measurement was too high so I'll try it again tomorrow. What would you have thought it to be?

tvboy wrote:

Hi Kiwi_Roy,
I did exactly what you described.

The spade terminal was clean, the starter mounting bolts are clean.

I used different ground points around the bike. The mounting bolts gave the lowest reading as one would expect.
Apparently my measurement was too high so I'll try it again tomorrow. What would you have thought it to be?

When I first did this I measured < 0.25 Ohms but that was on an earlier Guzzi a VII Sport with Valeo starter
The Bosch starters I have measured were very similar
I will check my GRiSO this evening in case I put you crook.
I measured mine as I outlined a few posts further back and measured 0.2515 Ohms

Hi all, I don't know if it would have any effect on the startus interuptus problem but on my bike (2017) The start button is an instantaneous button. That is, press and release. The starter cranks until the engine fires.

I am wondering if holding the button down during the start cycle would have any detrimental effect. As in, could it contribute to the the problem ?

I know very little about the Dark Art of Electrickery and don't know if earlier models have the same start button properties or not.

As a side note, I also pull the clutch in when starting. I read somewhere (manual ?} to do so. I guess less spinning mass = less load on starter. ?

OK, .9 ohms is very high.
Either way it's worth making a preemptive fix.

tvboy wrote:

OK, .9 ohms is very high.
Either way it's worth making a preemptive fix.

Just hold off a minute, I may have confused you, the coils are ~ 0.25 Ohms but you want the wiring and switches to be as low as possible the more current through the solenoid the better it works.
The strength of magnetism produced by a coil is the product of the number of turns in the winding * the current through it.

Agreed. Regardless, the potential for a future problem exists so
I'll do the fix and put it behind me.

thanks again

tvboy wrote:

Agreed.   Regardless, the potential for a future problem exists so
I'll do the fix and put it behind me.

thanks again

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The Roll-your-own fix is to cut the yellow wire before it splits to relays 2 & 3 then feed them from a separate fuse direct from battery.

In other words
Terminals 3 of relay 2 and terminal 5 of relay 3 are now straight from the battery

So it appears the yellow wire (that winds its' way around the whole frickin' bike) is the batt+ that supplies power to the start relay and ultimately the solenoid. What could go wrong?

@kiwiroy
I followed your step by step (I think it was yours )
cut yellow wire at solenoid,wire with inline fuse soldered in and connected to battery.
first press , sweet Italian opera
thanks craig

tvboy wrote:

So it appears the yellow wire (that winds its' way around the whole frickin' bike) is the batt+ that supplies power to the start relay and ultimately the solenoid. What could go wrong?

If you were Luigi looking at the schematic and see just one coil, take a digital multimeter stick it in series with the yellow wire you will see 10 Amps so a 15 Amp fuse seems adequate. If he used an old analog meter he might just catch a little blip of the needle.
Now you know there are actually two coils and they have an inrush current of 47 Amps would you run it all over the bike, I don't think so.
The 47 Amps only lasts about 10 milliseconds but if you don't get it the solenoid could sit all day drawing 20 Amps, that's what pops the fuse.
Changing the fuse for a 20 makes it last longer but it wont work better, you need more current for that.
Almost every Guzzi for the last 40 years has suffered because they don't draw the solenoid correctly.
Bosch, Valeo & Lucas starters all have 2 coils.
Wouldn't you think the factory would figure it out, actually I see evidence they are trying, every now and then they make changes like adding extra relays.

Thanks Kiwi_Roy

I don't mean to beat a dead horse on this topic.

After thinking about this I am strongly leaning toward just locating a new weathertight Bosch 50 amp relay near the solenoid using the existing solenoid wire as the trigger to it. The new relay coil draws <.2 amps. Well within the scope of the Guzzi wiring capabilities I think. A new 50amp inline fuse and new #10 wire from the battery to the relay and on to the solenoid would finish it.
Do you see any reason why this would be ill-advised?

Actually, I realized I could locate the new relay under the seat near the main 30 amp fuse and bring the solenoid wire back up to meet it.
That would be an improvement.
The OEM solenoid wire would remain intact and could be reused as intended.
Any other reasons I'm not thinking of why this is a poor decision?

tvboy wrote:

Thanks Kiwi_Roy

I don't mean to beat a dead horse on this topic.

After thinking about this I am strongly leaning toward just locating a new weathertight Bosch 50 amp relay near the solenoid using the existing solenoid wire as the trigger to it. The new relay coil draws <.2 amps.  Well within the scope of the Guzzi wiring capabilities I think. A new 50amp inline fuse and new #10 wire from the battery to the relay and on to the solenoid would finish it.
Do you see any reason why this would be ill-advised?

No, a 15 Amp fuse is adequate, the pulse of current is so short it doesn't have time to heat the fuse, there's less heating in 40 Amps for 10 milliseconds than 30 Amps for 20 milliseconds.
40 x 0.01 = 0.4 Amp Seconds
30 x 0.02 = 0.6
20 x 0.1 = 2
20 x 1 = 20
see how the heating goes through the roof when it takes too long to pull the solenoid in
As an example mine dropped from 50 milliseconds to 15 with a bit larger wire, remember the high current only lasts as long as it takes to pull the solenoid in then the current drops to < 10 Amps.

Adding an extra relay does mean you don't have to snip the yellow wire, that's all, it's not the way I would do it.

Note: providing a better feed for the start relay doesn't alter the logic, the starter still wont crank unless the key is on and the ECU is happy, it's still safe, just like the earlier GRiSO 1100

I see your point.

and I meant to write 15 instead of 50 so thanks for catching that.

marcdavo wrote:

Hi all, I don't know if it would have any effect on the startus interuptus problem but on my bike (2017) The start button is an instantaneous button. That is, press and release. The starter cranks until the engine fires.

I am wondering if holding the button down during the start cycle would have any detrimental effect. As in, could it contribute to the the problem ?

I know very little about the Dark Art of Electrickery and don't know if earlier models have the same start button properties or not.

As a side note, I also pull the clutch in when starting. I read somewhere (manual ?} to do so. I guess less spinning mass = less load on starter. ?

I don't think it would have any effect, I think the Startup Maintenance relay was added to later CARC bikes to allow for just that.
I always do the same with the clutch it won't crank in gear unless you do.