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Discussion Starter · #1 · (Edited)
Good Morning Guys,

as my Brutale 750 S, 2005, has been running flawlesly in the last years (ca. 15.000 km), I got her for a spin yesterday and after an half an hour drive, she startet to run wierdly. So I stopped, turned it of and then started the engine back up and the failure was back. I suppose that one of the cylinders ins not working, as she sounds really weird and also vibrates, but it doesn't stall. So I went back home and the first thing I did was, I put her in the garage, changed the spark plugs that have done 10.000km, with the NGK Iridium, inspect the champions spark connectors and there was nothing odd about them. So I started her back up and the problem was still there, between 2.000 and 4.500 revs, you feel the vibration, but after that, it feels "normal", also there is no "backfire (rattling sound when you go of the throttle)" comming from the exhaust as it is the issue at the low revs. Do you have any suggestions, what it my be? How can I test the ignition coils or the connectors to it?

Details about the bike:
Year: 2005
Mileage: 30.500km
EEPROM: Brutale 750 Corse (from Merc07) at 20.000km
Exhaust: HP Corse Hydroform - at 20.000km
Sparkplugs: NGK Iridium CR9EIX - recent
Air Filter: BMC - 20.000km
Valves sync - 20.000km
ECU is 16M

I assume, that the problem is in the ignition coils, so I have a question, abou the BERU ZS378 ignition coils. I didn't find the topic if they fit the Brutale 750 S, but I assume they do, as @fat has mounted them in his 910R, that also has the Magneti Mareli 16M ECU.

Champion with BERU replace

I have found also a BERU ZS377 that should have the same connector as the Original Champion Coil. (@Admin, please correct the link if I'm not allowed to link the shop) Does anyone have some experience with this kind of BERU Coil for "Benelli"?

If that is correct, I would love to recieve a short feedback.

Thank you for any suggestions in advance!
 

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Old Wing Nut
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Question.... how long since fuel filter and internal fuel lines were replaced? This may not be ignition at all.

Did all 4 plugs removed have a similar appearance? A single bad coil would result in one plug being black from mis-fire while all other plugs would be normal (white to light brown).
 

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Discussion Starter · #3 ·
Hi @esq'z me

thanks for your reply, the Fuel Filter was changed 5000km ago (ca. 25.000) then I also made the check of the internal fuel lines. But I think that if it would have been an fuel issue, that the engine would struggle and choke more in high revs because of the high fuel consumption and not in the low ones. I also think that there would be no back fire ("bang's"), as that is the issue now, including the vibration and you can hear that one cylinder is struggling. :confused:

Today I'm going to check which of them is cold (if so), and get back to you.

I've checked the old spark plugs (all 4 of them) and they were all "normal" light brown colour. But I was a little surprised, how fast the "copper" ones are being worn down (10.000km's). :rolleyes:

Cheers,

Ziga
 

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Discussion Starter · #4 ·
Just give a little heads up...

I have started my Brutale yesterday and let her to warm up, took her for a short spin and it was working perfectly. So I'm planing to give her a longer ride on the weekend, to see how it would react on the long runs. But I'm a little sceptic about it, as right after the change, the error was still there, and now after 2 days of standing still everything is working.

I'll give you a feedback as soon as I manage to ride her a little longer.

Thanks for your Support, you are all great!

Cheers,

Ziga
 

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Discussion Starter · #6 ·
Hi @Miko my friend and savior!

Of course, I drove her to Dubrovnik this year! ;-)

This is telepathy, I was planing to contact you this week about this issue, but you were faster than me! :):D

Yes, you got it right, as soon as it warms up a bit, the problem starts as one of the coils is not working properly, but it didn't fail completely. So I'll have to measure the resistance of the coils, but there is no information in the manual about the exact numbers of it. So I'll have to improvise a little.

Do you guys, have any suggestions how to find a faulty coil, that didn't fail completely?! I'm open to any suggestions.

Thank you in advance!

BR,

Ziga
 

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As I explained to you in the PM, since it's semi-edefective and error occurs only in specific conditions, connect the vacuum gauges and observe carefully. Let it run idle or on a very small throttle, at the moment of coil failure on one scale there will be a significant deviation in pressure.
Just in case, you can swap the coil location and repeat the test.
Let us know how it went.
 

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... So I'll have to measure the resistance of the coils, but there is no information in the manual about the exact numbers of it. So I'll have to improvise a little....
The resistance values are in the Electrical Section of the workshop manual.

Font Line Terrestrial plant Parallel Engineering
 

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Discussion Starter · #9 ·
@silentservice703 thank you for your information and the reply!

But I would like to know in which Workshop Manual did you fund this informations, as I looked into all of the of the Team Double 3 Racing and I didn't found any of the informations.

And also the ignition coils on the B4 750 S look different than your picture above with no Information about the winding resistance, except that of the Fuel Injector.

Product Rectangle Line Font Slope
 

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Well, @Ziga_SLO - Yikes! Another case of assumption gone bad. You are correct. I assumed the 750 B4 would b ethe same as the 750 F4 for that year and pulled up my F4 750 S manual because, sometimes, there is more information in one than the other.

That proved to be a bad assumption in this case. I would test each of my individual coils fo rcpontinuity and similar resistance readings. If one was far different from the others, I would call that one bad I suppose.

Sorry for the confusion.

I know the VDST software tests coil function, at least on my F4 312R, but I do not see that information in the B4 750S 2005 manual either.
 

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Discussion Starter · #11 ·
@silentservice703,

no hard feelings at all. As I have already written with @Miko I will put on the synchronizer/vacuum readers and there I can see which one doesn't work properly. This would be the easiest way to troubleshoot and to find the coil that has issues as the coil is still working, but it has hick-ups all the time.

Thanks for your effort and support, I appreciate it!

I'll give you a heads up on the outcome as soon as I come to it. :)
 

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I think you will find the stick coil resistance readings are similar to the F4 2 lead coil pack. That is: primary will be around 5 ohms and secondary will be around 7K to 15K ohms (noise suppression resistor may be present).
A typical Japanese stick coil measures 1 ~ 1.5 ohms primary and 6.5k ~ 9.5k ohms secondary.
But if this problem is only when warm and running you may not see the bad coil with static resistance tests.
An infra-red temperature measuring gun on the header pipes will show which cylinder is cooler than the others, and therefore the failing coil. Easy to do while out on a ride when the trouble begins.
 
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