trim pot : LUSENET : MV Agusta F4 : One Thread

Can someone tell me where is the trim pot is located for the FI?...and what rpm range is effected by it?

-- jim stanton (, May 14, 2001


The trim pot (potentiometer) is located in the CPU adjacent to the removable EPROM. It is recognized by its white nylon slotted head (and should be adjusted with a non-ferrous nylon screwdriver). It is used to adjust mixture so that the CO measured at the exhaust at idle is between 3-4%.........

-- Larry Wolf (, May 14, 2001.

End of 99 I went on the factory for technical upgrade. Very interesting. We spoke a lot with Goggi, the chief engineer for the motor and spent two days with Bruno (ex-Aermacchi engineer) disassembling and assembling the F4 motor, than we spent one day more working with the software built to modify the carburation settings. Factory employees in the end of the line, tune the bikes with this software (and throttle angle) for California, Swizerland or rest of the world (CO 4%), but never touch this trim pot. We also specially ask the question (because on Ducatis, tune with the trim pot is common)and Bruno said me again that on this new Marelli system even at Factory they NEVER touch this..., they try but than they have to return the box to Marelli factory.... I don't know if right or not, but Bruno seems to knows a lot about the job and I think these informations are right.

Let your own idea but think twice before touch this nice trim pot...

Bests regards.


-- Laurent Gaberell (, May 15, 2001.

I think Laurent's advice is very sound.......

-- Larry Wolf (, May 15, 2001.

The factory will always tell you to touch nothing...if we listen to that...we will never get any more performance out of these things.

-- jim Stanton (, May 15, 2001.

I agree with Jim concerning what factory tells, but in regard of warranty they can't say "let's go guys touch everything you found on the bike". Just think that than on the shop, it could be your bike...but for the same reason they spoke about tips concerning bike they know very well for what to do and what you doesn't.Bruno is not from warranty service, he's mecanic and like for some other informations about tyres and others things, he spoke with technical state of mind, really!!!

Best regards


-- Laurent GABERELL (, May 16, 2001.

OK Jim if you touch the trim pot, let me know what happens... I'm not those who says 'take my word for it, it's the only way of thinking'. And for me next week i'm going to change my exhaust system and EPROM and instead tuning the CO value with the trim pot I will modify it with the original MV Agusta software as used on the factory. Than I let you know what happens ok ? This we will learn more about the Marellis...I will also ask the question to Tom who works on softwares for Flow benches for Factory tuning USA, he loves all Marellis systems for cars or for bike and know that very well.



-- Laurent GABERELL (, May 17, 2001.

Laurent, I will be interested to know how you make are probably right about the pot but..sometimes I am a hard head and have to see things for myself, hehe

-- Jim Stanton (, May 17, 2001.

Same for me Jim but like you it's always for learn more about bikes. I never heard about this MV software but in the factory, the friend of me who is MV dealer bought one and we learn to work with on the factory (I'm customer but the friend says that I was employee on his shop...).You just have to plug your bike on a computer equiped with this software and than you can open a window. You found throttle opening historic in graphic form, ignition timing, revs historic, CO and more. Note that software is only available for MV dealers. On the Factory they plug synchro column, CO analyser and Notebook and tune each bikes so.


-- Laurent GABERELL (, May 17, 2001.

Wow!!!!! now we are talking are lucky you have that good friend at your dealership....maybe i could talk you into burning me a copy of that software????????......I dont think my dealer would be to keen on doing that for me, you lucky dog you. let me know how it goes.

-- Jim Stanton (, May 17, 2001.

First of all it's not my property and then it's delivered with a wire and it seems that wire is very sophisticated especially concerning the plugs. The whole thing is part of MV dealer tool kit and the whole kit cost worth than CHF 15'000.--. But even if for me it's free, I always paid a little something to the friend.I think it's better way to have good material and good results, just remember 10 years ago you have paid a day of labor on carburettors for set them and racing carbs where very very expensive...


-- Laurent GABERELL (, May 17, 2001.

Well I had to ask, hehe

-- jim stanton (, May 18, 2001.

I have fitted sil motor pipes to my bike and have been told that i will need to reset the CO to 4%. I have blagged a CO tester but am now concerned about delving into the brain!!! Help

-- ian hall (, May 30, 2001.

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