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Single TB 750 AND V7Mk2 e.f.i. Accessory

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V7Chris View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote V7Chris Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2017 at 22:32
Originally posted by oldlegs oldlegs wrote:

V7chris, I took my finebau off my v711 you can try that if you want, they only take about 20mins tofit. Steve.

That's very kind Steve. I would like to take you up on that offer if I may. I will pm you. I am curious why you took it off though, did you find it to be unsuccessful?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Leofric Quote  Post ReplyReply Direct Link To This Post Posted: 17 Sep 2017 at 00:25
I lost patience with my v7.2 special and exchanged it for a Honda CBF1000FA which so far seems to do everything well as you would expect a modern bike to do without the expense of modifications. No doubt the mpg will not be as good as the moto guzzi but I couldn't afford to sort out the 'riding over a cobbled street' suspension. Riding below 3000rpm not good either . Clutch was fine, cornering, running above 3000rpm, acceleration, shaft drive, controls, general handling and lightweight all good - MG comfort gel seat not that comfortable.
Basically I liked the bike apart from the flaws mentioned - a pity.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldlegs Quote  Post ReplyReply Direct Link To This Post Posted: 18 Sep 2017 at 22:04
Originally posted by V7Chris V7Chris wrote:

Originally posted by oldlegs oldlegs wrote:

V7chris, I took my finebau off my v711 you can try that if you want, they only take about 20mins tofit. Steve.

That's very kind Steve. I would like to take you up on that offer if I may. I will pm you. I am curious why you took it off though, did you find it to be unsuccessful?
From brand new my V711 had the small throttle low rev hesitation and after the 1st service was no better so I bought the Finebau and it was a worth while improvement. Then about 18 months any 12,000 miles later out of the blue after a short stop when restarted the engine did not respond to the throttle position for a few minutes, it did this a few times over the next couple of weeks. I removed the Finebau as a process of elimination and it made no difference whatsoever, the same problems continued. Then after reading posts on different forums it was suggested to disconnect the cables from the lambda sensors which I did and touch wood the bike has been ok since. I was told the V711 would get better and better for the 1st 10,000 miles and it has so never bothered to refit the Finebau.Steve.
Current: Beta Motard M4. Beta Motard tourer. Beta Super Motard. Beta Alp. Moto Guzzi V7 11 Stone.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2017 at 15:34
I have done the same change as Steve.......removed the lambdas, put stainless plugs in the holes in the exhaust and 3500 miles later no problems.   Just a smooth running engine. Only other engine change is Mistrals with the db killers fitted.
Andyb
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldlegs Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 2017 at 21:05
Andyb, I think it was you suggested uncouple the lambda's, thanks, can you tell me what size plugs I need or where to get them from Steve.
Current: Beta Motard M4. Beta Motard tourer. Beta Super Motard. Beta Alp. Moto Guzzi V7 11 Stone.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 25 Sep 2017 at 08:42
Hi Steve,
Always nice to have a cheap, reverse-able solution to a problem! Someone else told me about removing the lambdas so I don't know who tried it first.
I got the stainless bungs from ebay, they are M18 x 1.5 thread with a copper washer.
Cheers
Andyb
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 25 Sep 2017 at 10:11
I had a Triumph Tiger 955i for some years and it had a similar system with the O2 sensors. If you just disconnected these it upset the mixture. O2 eliminators are available which give a fake signal back to the ECU so taking the actual sensor out of the loop. In fact all these are is a resistor (I believe 330 ohms).

The real answer with the Tiger was to remap the ECU using TuneEdit free software so that it ignored the O2 sensor altogether although I have no knowledge of the Guzzi system.
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 25 Sep 2017 at 12:33
Removing the lamdas does seem too easy a fix, but on these bikes (1TB V7 with Mistrals) it does seem to work.

My understanding is that the lambdas make the ECU operate closed circuit and weaken the mixture below 4000 rpm in order to make the engines comply with Euro emissions. As a result the engines are snatchy in this rev range. Above 4000rpm the ECU operates open circuit so whether the lamdas are there are not is irrelevant. So removing the lambdas makes the ECU run open circuit below 4000rpm, and richens the mixture but does not change things at faster engine speeds.

It is almost like Guzzi designed the engine to run open circuit throughout the rev range but then had to add lambdas to get through the Euro emissions regulations - but this is totally a guess. All I know is that removing the lambdas transformed my bike. I would have sold it if I could not have got rid of the low rpm snatchyness.

Engines like the Triumph 955 are different beasts and a lot of ECU tuning is done to improve power higher up the rev range, so I am sure that you are right if you say that removing the lamdas does not work on them. I always kept my 955 engined Sprints standard.

AndyB


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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 25 Sep 2017 at 14:58
Yes, as I say I am completely ignorant about the Guzzi system. With the Triumph, it tried to correct the mixture where the target air/fuel was in a particular range (I can't remember what) which coincided with the 3-4000 rpm mark. That made it stumble and run erratically. What made mine absolutely smooth was to adjust the fuelling map so that it was in open loop (by making the target 12.5).

I never changed the maps at other rev ranges as I was very happy with the way it ran there.

Received wisdom with the Triumph was that merely removing the sensors without putting a resistor in upset the fuelling but I never tried that.
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote R100SRS Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 20:00
I recently changed a BMW R1100RS for a V7 cafe classic (mk 1). The BMW was fitted with an accelerator module, a plug in device which sends the ECU 20 degrees lower temperature than it actually is, in turn increasing the fuel by around 6%. It worked well, as to meet emissions controls the BMW, like many injection bikes ran pretty weak, so any increase in fuel could only help. (Much better with carbs - at least you an lift the needles to get more fuel).
I was expecting the V7 to be the same; but no - it runs very well even though it has a pair of Lafraconni silencers fitted. It’ starts well, runs and pulls well and compared to the BMW is a joy to ride. It can pop a little on the overrun, but that adds to the character of the bike.
My guess is that the problems that the Mk 2 & Mk 3 have, is related to the tighter emission standards that they have to meet Andy in doing so running leaner that is ideal.
I’m glad I went for the Mk 1........
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Adam Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 2017 at 06:30
Yes same bike as mine, no problems.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote V7Chris Quote  Post ReplyReply Direct Link To This Post Posted: 27 Oct 2017 at 06:12
Well the Finebau compensator I got from Oldlegs sorted mine out. No idea what electrickery is involved though, it may just be an empty box which has the effect of disconnecting the lambda sensors for all I know. Which brings me to my dumb question, why didn't you just unplug the lambda sensors and leave them in situ so that you don't then need blanking plugs?
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote V7Chris Quote  Post ReplyReply Direct Link To This Post Posted: 05 Feb 2018 at 16:02
Originally posted by oldlegs oldlegs wrote:

Originally posted by V7Chris V7Chris wrote:

Originally posted by oldlegs oldlegs wrote:

V7chris, I took my finebau off my v711 you can try that if you want, they only take about 20mins tofit. Steve.

That's very kind Steve. I would like to take you up on that offer if I may. I will pm you. I am curious why you took it off though, did you find it to be unsuccessful?
From brand new my V711 had the small throttle low rev hesitation and after the 1st service was no better so I bought the Finebau and it was a worth while improvement. Then about 18 months any 12,000 miles later out of the blue after a short stop when restarted the engine did not respond to the throttle position for a few minutes, it did this a few times over the next couple of weeks. I removed the Finebau as a process of elimination and it made no difference whatsoever, the same problems continued. Then after reading posts on different forums it was suggested to disconnect the cables from the lambda sensors which I did and touch wood the bike has been ok since. I was told the V711 would get better and better for the 1st 10,000 miles and it has so never bothered to refit the Finebau.Steve.


Steve, I seem to be experiencing a similar issue. As you know, I fitted your old Finebau unit and it certainly improved the low rev/part throttle. Went away to work overseas for a few weeks in November and got my neighbour to turn the bike over for me after a couple of weeks. Ever since then, it has an intermittent habit of failing to respond, sort of feels like fuel starvation but although I can't confirm, as though it is only firing on one cylinder. At idle it is fine and with no load it will respond to throttle input but sluggishly. Then after a minute or two fault dissapears and runs like a swiss watch. Does this sound familiar? Obviously I will strategy with disconnecting the Finebau to eliminate it. No other mods at all and 7k on the clock. Anyone else experienced this?
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldlegs Quote  Post ReplyReply Direct Link To This Post Posted: 05 Feb 2018 at 16:39
Hi Chris, sorry to here you are having problems, I never got the feeling my bike was running on one cylinder, my bike suffered most after a short stop such as calling at a shop for a few minutes and then restarting it would sometimes not respond to the throttle position for a minute or two and then be ok, sometimes for a few days other times it would do it the very next time I had a short stop. Hope you get it sorted soon Steve.
Current: Beta Motard M4. Beta Motard tourer. Beta Super Motard. Beta Alp. Moto Guzzi V7 11 Stone.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote motopete Quote  Post ReplyReply Direct Link To This Post Posted: 05 Feb 2018 at 20:17
Hi Chris, your symptoms are almost the opposite of what I'd expect... Here are my thoughts ~ brace yourself!

When you start the bike from cold it runs on a fixed fuelling map that's ever so slightly rich, whilst the lambda sensors heat up. Once the lambda sensors are hot they generate an output voltage which the ECU detects; the ECU then goes into closed loop mode and regulates the mixture based on feedback from the sensors, alternating weak/rich/weak.... etc

The crucial thing is "weak" means very weak, "rich" means just about rich enough to run smoothly. So on average the engine's running weak (hesitant and uneven) with brief periods at the end of each weak cycle where it's far too weak and won't respond to the throttle for a moment or two.

If you start your bike from cold and don't touch the throttle, you should find it initially ticks over quite smoothly (ECU open loop) then after a few seconds  or 10's seconds you'll notice it go lumpy - that's when the ECU switches into closed loop mode.

The Finebau device is trying to raise the voltage at which the lambda sensors indicate "weak" and get the ECU to start richening the mixture before it has a chance to get too weak. This sounds fine in principle but the lambda sensors have a very sharp characteristic between indicating rich/weak; in otherwords altering the voltage at which the ECU switches only has a small effect on the fuel mixture.

How do I know all this I hear you ask?  Well I've spent many hours with a 'scope on my bike after building a Finebau-type device. Oh yes, I know how to enjoy myself Wink
I also noticed when I took my bike in for its 1st service the diagnostic S/W displays something called "mixture correction". It started at 0% when the engine was started then after a few seconds started going negative, to around -2% or -3% I think. I assume this means weaker.

In practise with my Finebau-type experiment I found it was also necessary to delay the "rich" indication back to the ECU by a few 100's ms, but give immediate indication when the "weak" threshold was detected. The average mixture (AFR) is then slightly richer. Still not as good as well set-up carbs but that makes sense because in closed loop mode the mixture is oscillating rich/weak/rich..., hence the engine reacts accordingly.

The upshot of all this is fixing the problem once and for all probably requires so called wideband lambda sensors. These measure AFR over a much wider range, so a change in sampling voltage has a much larger effect on the mixture. You'd still need some electronics between the sensors and the ECU, the electronics determining the voltage at which you declare "weak" and "rich".
Only thing to be aware of is emissions control, but to my mind making the mixture just rich enough for the engine to run smoothly should give acceptable emissions.

IMHO the standard set-up can be downright dangerous if you're not used to it, for example opening the throttle and nothing happens for a second or 2... your concentration turns to engine management instead of the road Shocked

I hope this rambling reply makes sense. This and the overly harsh suspension are the only 2 things that spoil this otherwise perfect bike for me.  I still enjoy riding it though Smile

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