Coil Testing

[Howling TerrorOutOfOffice]

Hi, I suspect a faulty coil or connection as when the bike warms up that's when the misfire happens.

It's a plug cap type that terminates in a 3 pin connector block.

https://www.rrd-preparation.com/23709/ignition-coil-motorcycle-mv-agusta-910-f4-brutal-brutal-rr-2004.jpg

Nothing in the workshop manual regarding correct values.
Bike is MV F4 2010.
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[WD Forte]

that looks like a coil on plug type to me
never played with them
this may help?

https://easyautodiagnostics.com/misc-index/two-wire-cop-coil-tests-1

If I understand it right the 3 wire types have a
+ve (power)
-ve (ground) and
trigger signal wire from the controller

It could be tricky to debug without a scope as a basic resistance test
may tell you little.

While Im rantin on...
I'll guess the bikes system may have a crank sensor and these have been known to struggle/break down when they get hot.
Again, a scope would really help
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[MCN]

It sounds like a coil unit fault. The insulation breaks down over time due to heat/cold cycles and wet-ness.
You could test insulation using an ohmmeter. I may pick up a difference between good one and a bad one. Might.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[G]

Any specific one you think is faulty?

You might be able to get an idea by swapping them around - then using a stethoscope (or screwdriver etc as one ) to try and see if the misfire moves with the coil.

[Howling TerrorOutOfOffice]

Replies appreciated; From memory I'm unable to leave the fuel tank connected whilst swapping out coils to narrow down the offending unit.

@WD Forte I'll check that the coils are getting 12v. Cheers for the link.
@MCN I'll be checking for any water ingress which would make sense as the last few rides were in very heavy rain and the bike was left out for a week.
@G No, the fairings are still on. I'll clean my ears in readiness.

Looks like I have a morning of tank in/out.
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[MCN]

[Howling TerrorOutOfOffice]

The oliday cottage didn't leave a garage key and my lock picking technique left a crease in the door. ...but yes heartless.
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Diabolical homemade music Bandcamp and Soundcloud
Singer songwriter, Artist and allround good bloke Listen to Andrew Susan Johnston here
The Harry Turner Project

[G]

If you can suspend the fuel tank (presuming in-tank pump), you may still be able to have it wired up.
Or just place it an angle while other bits are hanging off - but then you risk it either hanging from the wires or bouncing down to the floor, neither of which are ideal on a pwetty bike.

[Hong Kong Phooey]

Measure primary and secondary resistance of all, the outlier would likely be the dud.

I just bought a cheap second hand set of four to cure my misfire - which oddly went away if a full bottle of redex was put in the tank, making me believe it was a fuelling issue (giving credence to the old adage that 97% of carb problems are electrical)
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[Teflon-Mike]

Stupid Question.. and 1st rule applies, I PROBABLY dont really want to know the answer.... it's Italian, and worse, a 'bespoke' italian.....

How much are new coil-caps?

Wait.. let me go get Italian flak-hat and flag first.. yes that will be the white one!!!!

Oh-Kay....

First off it's an intermittent..... these are the very devil to bottom, cos if it works, you cant find it... if it dont... you only 'think' you have found it, when it works again.... until it dont! And it Italian!

Have you thought of trading it in for a Honda? Or are you hoping to descover the joys of Latin Masocism with it?

GARAGE DOOR!!!!! IF you had succeeded in opening said garage door, by force.... what did you hope to do? Was it sort of a falorn hope, that if you helped the Twockers along a bit, maybe they'd 'fix' it in their get-away, and either you'd get it back and not have the headache of fixing it, or never see it again, and not have headache of fixing it.... and easier to fix a garage door than an italian motorbike, kind of thing?

Coil-Caps.... err.. how much... eek... If they are the top of the list of suspects... if cheap enough, could you not diagnose by replacement... if miraculousely cheap enough, replace the set, if problem goes away, job done. If not, weren't the coiul-caps... you have spares for when it's thier turn... look elsewhere. If almost cheap enough.... replace one.. if problem goes, that was the culpret... if not, lift tank, swap the new one with next in the line, try again, till all 4 tried, or problem goes.

NOT the kind of mechanics my old Grandad would have approved off. 'Fitters-Fault-Finding' he called it... but has its place, and if it is coils, at some point you probably will have to cough up whatever one or a set will cost anyway, so trying to find a faulty coil-cap that is only a faulty coil-cap when it decides to give a latin shrug and bugger off on siesta, by test, could be an even more sure way to a nervouse breakdown with italian Spagetti than something less sophisticated.. Like a Moto-Guzzi headlamp switch... which is bad enough.. I K-N-O-W!!!!
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[Howling TerrorOutOfOffice]

Fires up and runs on 4...warms up and slight misfires start.
The bike isn't ancient and shares electrics fitted to other brands. It's 8 years old and been a good girl upto now.

The garage door was shonky n loose so was worth a wrestle. The venue was remote.

Coils £40 and upwards.
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Diabolical homemade music Bandcamp and Soundcloud
Singer songwriter, Artist and allround good bloke Listen to Andrew Susan Johnston here
The Harry Turner Project

[Teflon-Mike]

[Fizzer Thou]

Has the OP got access to a laser guided infra red temperature reading device?

https://www.toolstation.com/shop/p92559

I have used a cheaper version so as to detect which cylinder on my Exup1000 was causing a difficult to diagnose misfire.In the end it was a mixture of aged silicone leads and two plug caps that were split along there seams and when hot opened up.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[G]

Good call - from a little over a fiver on ebay.

I've got one of these that seems to be pretty accurate - no laser, but being more compact can often get it closer - https://www.ebay.co.uk/itm/142716054962 .

[MCN]

I assume the IR temp tool is to be used to find a cold exhaust pipe?

Dead cylinder hath no fiyah.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[BTTD]

Water will do the same. Spray it on the headers. The least sizzle = not firing.