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Discussion Starter #1
The dreaded intermittent stall issue..

I have a 2005 MV Agusta F4-1000 that I've had for awhile and ridden happily for over 10yrs now both for track and street. I've had some things come up over the years including the EBS relay etc and have been able to troubleshoot and address most myself with help occasionally from fellow forum members here on the site as well.

I have a couple of other bikes and don't ride it all the time, but more recently I've had a kind of crazy intermittent power-interrupting problem develop that causes the bike to lose power mid-flight repeatedly once at temperature and almost immediately return power over and over again repeatedly until the bike eventually fails and stalls out completely.

I'm not talking the typical EBS relay- Lose a cylinder or two, but rather a full lose of entire power momentarily before its repeatedly and rapidly restored on and off causing and on-and-off scenario like a bronco before the bike stops all together.

Anyone have any ideas on this? or familiarity with this type of condition on the MV before?

So far I have changed the fuel pump assembly, filter and hoses etc- all new along with new set of ignition wires (*which did need to be changed really at this point anyway) and plugs of course. Although the bike feels great otherwise and pulls with great power from the start, eventually after a few miles and the bike is also fully up to proper operating temp the problem persists, which brings me next to the ignition coils that I haven't changed yet, but I'm honestly not sure is going to work anymore.

Any thoughts or experiences in this area?

PK
 

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Engine cuts in and out but dash still on, like someone is playing with the kill switch ? Sounds electrical, dodgy contact, iffy switch ( clutch or side stand switch?), kill switch itself, the list could be long!
 

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...a bad ground to the ECU....
 

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Dash power stays on, just engine stops?
CKPS is sitting on the side of the engine, subject to heat and vibration. Test it....resistance, insulation, peak voltage output. Both when cold and again after warm and problem begins.

This is a very likely culprit (relatively rare, but not uncommon on higher mileage bikes of all brands). One of 3 primary inputs for EFI operation.
 

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Ed, what is CKPS?
 

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Discussion Starter #6 (Edited)
Yes the power to the dash does stay on and yes the bike does have now what would be considered a sizable amount of mileage for a Italian exotic (about 20,000). And although I haven't journeyed with the bike far at all now since the problem began at the end of last season it does appear to get progressively worse as you go along and have been riding it for a few miles, with the bike later restarting again once given the time to cool. The Crank Position Sense
 

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Ed, what is CKPS?
Crankshaft Position Sensor...that thing down on the left side that the "phonic wheel" spins around next to. Essential signal for EFI (Where is the piston in the stroke, and how fast is it moving). When they start to fail it usually manifests itself as heat rises. Signal gets weak or goes away. Usually a short to ground in the winding.

Don't know the peak voltage (RMS) spec for the MV (haven't looked to see if it's listed) but a common number is >2 volts. Comparing cold to hot readings is the best test.
 

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I just didn't recognize the acronym....
 

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Discussion Starter #9
Yes esq'z me- I have to say I believe your are on to something here. The behavior is unlike anything else I've ever experienced on a bike in general and is even unique to a typical intermittent wiring issue, such as a short, bad or "going" fuel pump or even a ignition coil having lost a winding etc. In this it's behavior would seem to lend it itself more to something like you are describing, such as the CKPS, or in relation to something the computer system is attempting to interpret signal from now failing.

I thank you for this, as I think you have given me a very good lead to go by here now.

If anyone has possession of the exact resistance readings I should look for in testing the current CKPS sensor and can share them here with us that would be great, otherwise I'm just going to do a bit more research myself before I proceed, but thank you brother- I think you've given me a good starting point to continue from now- Much appreciated!
 

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enough of the idiotic acronyms....

Chuck and​ I didn't know what you were talking about Ed.......type it out......

This is a Worldwide Forum.......not everyone​ speaks technical English and most translator apps suck at technical terms

look in the Engine Manual......

what's a "carter"?.......if you research it , it means oil sump in automotive usage.....chain guard on a bicycle​....

they meant crankcase......

then they call the crankcase a "bedplate"

See what I mean?

:wink2:
 

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Chuck and​ I didn't know what you were talking about Ed.......type it out......

This is a Worldwide Forum.......not everyone​ speaks technical English and most translator apps suck at technical terms

look in the Engine Manual......

what's a "carter"?.......if you research it , it means oil sump in automotive usage.....chain guard on a bicycle​....

they meant crankcase......

then they call the crankcase a "bedplate"

See what I mean?

:wink2:
What can I say..... Noel, you really have to catch up. That is the standard SAE accepted abbreviation. I'm not using obscure nomenclature here. Give me a break.
 
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you sort of missed the point Ed

What can I say..... Noel, you really have to catch up. That is the standard SAE accepted abbreviation. I'm not using obscure nomenclature here. Give me a break.
Google it Ed, no where is it mentioned as a SAE acronym......

go back and read my rational for typing the entire name of the part......there are people on this Forum that don't speak English
 

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I HATE "Acronyms" -- They are ambigous, unless solidly locked in context, they are often illogical, made up, dreamt up or "doctored" to sound "fancy" --
I would as a former editor of scientific texts, return manuscripts that did not describe/explain at least once, EVERY Acronym used at the start of the manuscript ..
 

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Google it Ed, no where is it mentioned as a SAE acronym......

go back and read my rational for typing the entire name of the part......there are people on this Forum that don't speak English
I'm sorry, you are right. I'll try to be more careful in the future.

MAP sensor is another one not to use. I guess I am just to accustomed to all the acronyms commonly used in current motorcycle servicing. Helps when writing reports. IAPS, ECTS, TPS, CMPS, CKPS, IATS, ATS, the list goes on.
 

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Discussion Starter #16 (Edited)
Ok- with the nomenclature issue now addressed, all being said and now having amassed a group of some of the brighter minds in MV knowledge here can I bring this back on topic for just a moment please and just ask if "we" think we are of the right mindset here on the issue at hand?.. namely the Crank Position Sensor being the most likely culprit or cause of the issue described.? :nerd2:

Thanks

PK/MV1
 

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I had an older Honda VFR where the "pickup" for the ignition failed regularly causing the bike to just splutter and then croak .. This part was immersed in the hot engine oil on the VFR .. so letting the bike cool off for 20 mins, and it would run again for 30 mins --- trips tended to have a lot of "Tea-breaks" until that got fixed ..
 

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Discussion Starter #18
Ok gotcha and completely understood DK. It close enough to what you're describing for me to have thought ignition for a moment myself, but too immediate and then repeated in succession afterward to jive I believe with a more typical ignition issue like your are describing you had with the VFR. It truly is more like it loosing track of itself, which almost seems to indicate something else in my case now. I'm ultimately not sure if it's the Crank Position Sensor or something along the lines of the throttle positioning sensor, but it is as Esq uez me had pointed out earlier something to do with operating sequence in my MV's case.

The bike again runs and rides great as per the norm for a limited but yet still random amount of miles before beginning with but a sputter, which progressively get's worse and or more pronounced before becoming completely unruly and intolerable, eventually causing the bike to stall out, shut-down and or fail completely. Each time restarting again when requested to do so, but only to shutter and stall again shortly thereafter. Given time to cool and or reset itself again the bike can once again be restarted and ridden once more, but by then also restarting the sequence once more as well.

I haven't repeated this sequence enough times to be anymore detailed then this, but this is I believe a pretty good description of my particular bikes scenario at the moment.

*On the last go around attempt- I rode the bike trouble free for about 5 or 6 miles from my house in Queens NY to the GW bridge in a attempt to make out for a ride with the boys upstate. Just before getting on the bridge she displayed the first sign of the sequence, with just a brief momentary power-loss (twice) at highway speeds, restoring itself as quickly as it came, but enough to be noticeable to me as the rider on board.
I took this as the only warning sign I needed to know she was still not well and turned off immediately at the following exit to turn things around and headed straight back home, which I was able to do without further incident but without any further confidence to ride her again since.
 

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?

Don't think it's heat doing it.......
Just tested my 910R...... won't go over 87C/188F on dash (MicroTec)

sensor 54C/129F

Now a broken wire or bad connection.....like the one on the thermistor for the low fuel light

:wink2:
 

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I'm sticking with the crank position sensor...

Your symptoms do not occur until engine has reached full operating temp, are progressively worse until complete shut down. The everything is fine when engine cools off. Right???

Got a digital volt/ohm meter (multimeter)?
Unplug the sensor and measure the resistance between the wires (should be simple 2 wire connector). I would expect a value in the order of 100~200 ohms. I'm sure there is a spec in the manual.
Next measure the resistance from either wire to the engine case. It had better be infinite on the highest scale the meter has.
Finally, set the meter on a very low AC voltage range, connect to the 2 wires and crank the engine. I would expect something like 2 or more volts...maybe as high as 5. Whatever, make a note of all your readings.

Now ride the bike until hot and acting up. Repeat the measurements. Resistance should not vary much and insulation to engine case had better still be infinite. AC voltage should stay the same. If not, there's your failing component.
 
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