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 Post subject: Paso 750 MARELLI coils output voltage?
PostPosted: Tue Mar 30, 2021 10:15 am 
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paso grand pooh-bah
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Location: Finland
Hi!

Have anybody measured OUTPUT VOLTAGE from Marelli coils ??? (...going to wires what leads high voltage to spark plugs via high voltage wires)

All advises are welcome,as my friend have such problem, that are his high voltage wires ok, or no. Also insulation tester connect to this thing, but just now, it is important to know Marelli coils output voltage (for measuring wires in right scale, 250V, 500V, or 1000V with insulation tester)

Normal multimeters use normally only 9V DC battery in Ohm scale and that does not work in this case.

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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Tue Mar 30, 2021 1:39 pm 
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paso grand pooh-bah
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model: 907 I.E.
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The output voltage should be several thousand volts and will depend on the ratio of the turns on the primary and secondary windings. It icould be somewhere from 20,000 volts to 50,000 volt. No idea how you measure that though! Why would you want to measure it? Normal check for coils is to check the gap the spark can jump.

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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Wed Mar 31, 2021 11:38 am 
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paso grand pooh-bah
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Joined: Tue Jul 29, 2008 9:50 pm
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Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
personally who cares Replace them.

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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Thu Apr 01, 2021 3:45 pm 
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paso grand pooh-bah
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Posts: 3073
Location: Finland
Higgy: Did You mean to replace wires, coils, or what, as You didnt say what to replace? I only want to help my one FRIEND, who is "fighting" with his 750 Paso as it have that Marelli ignition system to keep his Paso as "original as possible" with that Marelli system.

BTW: I have Kokusan system in my 750 Paso, so this thing is not connected to me at all....

And what did You mean by saying: "personally who cares" ???

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KTM 990 Adventure -08 metal dark grey
Paso 750 -89 red/metal grey
Paso 907IE -91 red/metal grey
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ST2 -01 red/metal grey
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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Thu Apr 01, 2021 10:30 pm 
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paso grand pooh-bah
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Joined: Wed Dec 05, 2007 12:35 am
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Location: Newzealand
model: 906 Paso
year: 1990
Hi Antti , Im not sure how you plan to measure Coil output voltage with an insulation tester. I think the thing to do is to check the primary and secondary windings and compare them to specs , the primary winding is real low , like 0.3 ohm ( so dont think its a misprint in the specs ) this alludes to a very short dwell angle . After that if the readings are ok I would temporarily hook coil primary up to battery and hold end of ht lead close to earth and disconnect power , you should see a spark as you do so . It should spark at least ΒΌ inch. Bit crude but give an indication of coil output. You could use insulation tester to check for leakage by testing between primary coil terminal and earth ,and plug lead and earth for secondary , then test between primary terminal and ht lead will test for leakage between the 2 windings. I would use no more than 500v to test and youd want to see about 20 mega ohms for each test .
Higgy has a good point in just replacing them if in doubt ....specially if it going to be in regular use , but if your wanting to preserve either originality or bank ballance its worth checking them out .

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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Fri Apr 02, 2021 12:49 pm 
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paso grand pooh-bah
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Joined: Tue Jul 29, 2008 9:50 pm
Posts: 3239
Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Antti, I would start with the secondary wires and plugs.I make them up with accel brand 8mm which is available everywhere here but there are many others Usually a good visual inspection goes hand in hand with a resistance check. Any white/gray spots means a leak.Check the wire routing usually anywhere the wire is close to metal. Remember the entire bike acts as a ground.As far as the rest swapping side to side can be helpful if all the resistance checks are good. An auto oscilloscope can check output voltage if some one still has one. Oscilloscope would be the preferred way to check for issues. Any issue would be obvious. A leak will show as a spike in the output voltage. These days Autel make one for 7Kusd a little on the steep side for most diyers but most decent repair shop will have one as they are the easiest and quickest way to go for any repair shop. Maybe you know someone who would be willing to check it out for you and your friend. BTW 20k volts is a typical output for a bike coil but can be as high as 50/60K with a decent coil and wires.

If his Paso has the one piece coil and wire find a repair shop with an oscilloscope. Sometimes you can pick one up for cheap on fleabay

https://www.ebay.com/itm/Upgraded-MUSTOOL-MDS8207-Intelligent-2-in-1Digital-40MHz-200Msps-S-Oscilloscope/294088784435?hash=item44790eba33:g:yJgAAOSwuNdgX6ld

can't say if this one even works its just what I found doing a search for auto oscilloscope.

https://www.ebay.com/itm/Fluke-Networks-Linkrunner-AT-2000-AT-2000-Auto-Tester/284223457498?hash=item422d09c8da:g:tZcAAOSwBTpgUnfE

https://www.ebay.com/itm/Fluke-95-Scopemeter-Portable-Handheld-with-case-power-adapter-and-leads/193960312635?hash=item2d28ef7f3b:g:oH8AAOSw2Zhfun4e

As you worked as an electrician maybe you have a high end multi meter. You can buy adapters to do this sort of scopeing. I have a fluke that could do it if I wasnt such a cheap bastard :smoke:

As i sold tools for 5 years I have hundreds of friends would do it for me just for asking and a beer or 3 :truck:

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Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie


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 Post subject: Re: Paso 750 MARELLI coils output voltage?
PostPosted: Tue Apr 06, 2021 3:28 pm 
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Joined: Thu Nov 29, 2007 2:38 am
Posts: 333
Location: UK
model: 907 I.E.
year: 1990
not sure why cause self harm trying to keep something ( the digiplex) that was fiffed only on a handful of bikes (mostly ended in USA and then back to EU as ther wend unsold) that was not intended for the bike, and because of the technology would not last 10 years .... go figure how is possible some are still working 30 years later.

The map sensor will fail, some of the components will go out of tollerance , not to mention the quality of the build , just open one and compare it to the modern ECUs , a picture says it all.

IF (IF) there are no other options, then yyou can get it fixed, but there are other options that are actually as good as the Digiplex, if not better.

That piece of junlk was fitted on 3000 bikes give or take, before they were Kokusans and after they kept fitting the Kokusans until they went IE.

the same goes for the coils, the dust might be the only thing keeping them together...

sorry for thge rant, but this is how one starts hating a bike... you get fixated in trying to keep iyt in a certain way , focusing the attention on the "thing" rather than enjoying riding the "thing"


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