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Discussion Starter #1
Hi,

I have a 910S currently in my garage that a friend from USA bought for going to this year's TT...recent introduction thread:

http://www.mvagusta.net/forum/showthread.php?t=172530

The issue right now is that it seems to have developed a fueling problem where it runs very rich most of the time. When starting from cold, it will cut out a couple of times if left on tick-over and below 4k rpm it is a little rough even when up to running temp. It still pulls strong through the rev range but smells very rich and under moderate/hard acceleration will throw out grey smoke and often pop between gear changes under harder acceleration.
This seems to be more pronounced after the service I gave it last week (Irridium plugs, BMC airfilter, oil & filter). I have been using super unleaded (99 octane) and it will be on the fuel light in less than 90miles...not massively unreasonable but maybe a bit thirsty because of the over-fueling?

I have booked it in for a rolling road session on Friday to see if they can diagnose anything but was wondering if any of the above issues sound familiar or obvious? The dynojet center I am booked in to says that if it needs a re-map (due to the exhaust) then this is impossible as the ECU's are locked and Dynojet UK don't list a PC for this bike.

Any advice or suggestions?

Thanks.
 

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Sorry your having trouble with the Brutale, I read your original post when you had just purchased.
I would suggest wait until the rolling road check it will direct you to a correct diagnosis, it may just need a tune and bought into line with the MV's specification, was it there when you picked it up? If so the new performance parts added would highlight the issue further. Good luck and keep us informed of your outcome.
 

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Discussion Starter #3
Hi Chris, no, nothing obvious when the bike was ridden back home on day 1....it was very difficult to discern any specific issues as it is significantly different to previous experience (all Honda, i'm afraid!) and it is so damn loud with the Corse pipe that it drowns out pretty much any other noise or obvious issue!
I noticed it wasn't running quite right after an 80 mile round trip last week - a little grey smoke on start up and a less compliant ride on low throttle....that's what instigated the service and subsequent reported problems.
 

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Where are you based ?

If you can get an afr bung or 2 fitted before the rolling road I have a data logger system that will log the fueling and ECU data - the EPROM can then be tuned accordingly - that is if the fuel map is what is at fault.

Make sure the idle afr and tps are correct to start with - if the fuel adjustment pot is tweaked out of spec then the whole map will be out.
 

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Discussion Starter #5
Hi Merc, I am in Worcester....is that anywhere near you?

It is the same mid pipe as on this thread:

http://www.mvagusta.net/forum/showthread.php?t=1289

So, has bung for an o2 sensor already.

I am guessing there are threads on here about checking and tolerances for idle AFR and TPS?
 

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Discussion Starter #7
So, spent most of the evening on the MV to see if there was anything obvious that may have been contributing to the problems as they seemed to only appear after I serviced it. My buddy (who's bike it is) suggested going back to the original plugs rather than iridium so that obviously necessitated removal of the tank and airbox. I found that the plug in cyl 1 was more 'coked-up' than the other 3 then noticed that the bell mouth on cyl 1 was also out of position...maybe lifted approx 1mm on the out side. Not sure if false air above the butterfly is an issue or maybe just a combination of non-iridium plugs, removing and refitting the airbox and generally taking more care during the rebuild process has had the desired effect.

Anyway, only had chance for a short ride around the block so will look to test it a bit further tomorrow...however, so far so good. No excess smoke that I could identify and definitely a cleaner throttle response at low/part throttle.

Thanks for the advice...will post once I have a definitive answer!
 
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