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Tomchri

Left sylinder running lean

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I wish I had the time to chase this kind of detail on a perfectly running bike. I'd take the spare time and forget the exhaust colour.

Ciao 

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44 minutes ago, Lucky Phil said:

I wish I had the time to chase this kind of detail on a perfectly running bike. I'd take the spare time and forget the exhaust colour.

Ciao 

Sorry cant help it,,, still learning here and like the thought of correctly fueling.    But if I hadnt seen it,,, I wouldnt have noticed it either.

Cheers tom.

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Maybe I should start a thread about this, but most every bike I have tested with a thermometer at where the pipes come out of the head have a temperature differential.

I have never checked the injector output on any bikes to see if they are the same, and I am pretty sure there is some variance.

My idea was to use the fuel offset table in the ECU map (via Tunerpro) to increase or decrease the fuel across the board by a percent or two or however much is necessary to match the temperature of the exhaust at the header pipe.

So essentially you would be matching the fuel output of the injectors by reading the temperature.

Or if you measured the flow volume using a 9V battery hooked  for a minute and calculated the percentage difference you could alter it by that difference in the offset fuel map.

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14 minutes ago, antmanbee said:

Maybe I should start a thread about this, but most every bike I have tested with a thermometer at where the pipes come out of the head have a temperature differential.

I have never checked the injector output on any bikes to see if they are the same, and I am pretty sure there is some variance.

My idea was to use the fuel offset table in the ECU map (via Tunerpro) to increase or decrease the fuel across the board by a percent or two or however much is necessary to match the temperature of the exhaust at the header pipe.

So essentially you would be matching the fuel output of the injectors by reading the temperature.

Or if you measured the flow volume using a 9V battery hooked  for a minute and calculated the percentage difference you could alter it by that difference in the offset fuel map.

Its far more complicated than fuel in temp out. There are a lot of variables some of which are compression differences, squish clearance differences, varying shapes of inlet ports that give different amounts of turbulence. All of these and much more affect burning efficiency and therefore what you see in the exhaust port and it all varies depending on what speed and load is on the engine.

For a road bike particularly there is an acceptable window of operation and as long as the engine performs well, carburates well and doesn't use too much fuel then delving into exhaust port colors is a little pointless from a practical point of view. Race engines are different of course but they are operating in a much narrower window right up against the limits.

The chances of burning an exhaust valve on a road bike due to tuning issues are pretty remote. If the map is that bad it'll be horrible to ride. Of course reading plugs and ports on a road bike is fairly useless anyway unless there is an extreme issue. thats why racers always used to do a plug chop at the end of practice and the straight as low speed running everywhere else just gave useless readings.

Ciao   

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I understand that it is a complex interaction of many variables. 

What we basically do is balance throttle bodies to try and compensate for most of the variables and in some cases match injectors. Of course we also try and make everything as close to the same as possible between the 2 sides, like valve adjust, compression (if it is off by more than a little), timing, etc.  

We are averaging all these variables out with how much air each side is sucking in by the TB balance.

To achieve an even better possible averaging of these variables in addition to the TB balance I was wondering if temperature equalization might achieve this?

Foe example, years ago on my earlier tonti bikes with distributors I would use dwell to set the points and not by gap. I would match the dwell for each side and not worry what the points were and I could achieve a better, smoother running  motor. The point gaps were usually not that close. By using dwell, this gave me the exact same duration of points being open and closed.

I'm just thinking of possible alternate ways to compensate for the mechanical variables that there is no easy inexpensive way to make the same between the 2 cylinders.

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I'm certainly not qualified to add anything to this, but a lean cyl would bug the crap out of me, and I would chase it to the best of my ability.

which would include coming on this forum and ask

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1 hour ago, footgoose said:

I'm certainly not qualified to add anything to this, but a lean cyl would bug the crap out of me, and I would chase it to the best of my ability.

which would include coming on this forum and ask

But who says its lean, images can be misleading but it looks fine to me. The r/h may well be too rich.  The only way to tell with any accuracy is to lambda probe each cylinder.

Unless you're prepared to do that then its just going to be a drawn out proposition. Are we willing to wait for a few thousand miles to see the color of the ports to ascertain whether or not its corrected every time you make an adjustment or try something, because thats what it will take? 

I'll watch the rabbit get chased down the hole with interest.

Ciao

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If it really bothers you, send your injectors to someone who can truly flow balance them. But I agree with Phil. It is not something I would loose sleep over.

To add to the dynamics of it, because it is a 90 degree V twin with a shared airbox and exhaust there will be differences between the fueling of the two cylinders. And at different rpms the differences in fueling may shift due to the intake and exhaust timing and the relationship that timing has with fueling. The intake pulses from one cylinder can affect the intake pulses of the other cylinder and vice versa. The same thing for exhaust. But since the timing between the two cylinders firing is not even, one cylinder fires and a short time later the other cylinder fires then the time gap to the first cylinder firing is substantially longer than the previous time gap. These uneven intake and exhaust pulse can and will affect how the engine breathes. Meaning, as the volumetric efficiency of the two cylinders changes the fueling will change with it.

Couple that with the difficulty of reading color as a indicator of lean or rich, I just can't see going down that road without more to go on. If you really are concerned, fit either O2 sensors or exhaust gas sensors to each header. Then see what you have. But really, the Guzzi system doesn't allow, as far as I know, individual tuning of the two sides. So, other than fudging the flow of the injectors what can you do? And fudging the flow of the injectors may back fire on you in ways you did not foresee. The most I can see doing, if you really feel compelled to do something, is have the injectors flow balanced. Replacing them you could easily end up in the same boat as chances are the new injectors aren't going to flow exactly the same amount any more than the existing injectors do.

If it really was lean, lean to the point it was detonating or running poorly, I could see worrying about it. But as far as I can tell it runs fine and I have not heard of any issues with it.

That is my two cents.

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Mine were old and worn and delivered differently and replacing them made both exhaust headers look the same. This didn't hurt, at least.

When I read through the posts above I can see only one conclusion: keep as much components straight and matched and level as possible.

Are the injectors listed in the OEM parts/alternatives list? They are available for Lancias IIRC and should come sufficiently matched. Green ones should be ok. Alas, I can't remember what the specs were or where I found them. Maybe Guzziology ...

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Gents,   I like all what Im picking up here, thank you :mg:  I know I shoud have called it sooti right cyl,  but conclusion , will clean the injectors, and keep on enjoying the  4000  to 7000 area.                    

Cheers tom

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Please correct me . You did swap sides with the injectors ? Did this condition stay on the same cylinder ?

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5 hours ago, gstallons said:
Please correct me . You did swap sides with the injectors ? Did this condition stay on the same cylinder ?

No
I have 2 extra injecktors, I changed the so called lean one. I shoud have changed the sooti one.
Took her for a 200km ride today, she runs great. I will take L Phils advice for know, before I take headers of again. Its great riding weather at the moment.
Will wait now til I recieve Martys cleaning tool, and then try measuring and cleaning.
I know it will put a smile on my face, if I can the same result as Luhbo did.
IPA time.
Cheers tom.

Sent fra min SM-G903F via Tapatalk
 

Edited by Tomchri
Name not correct

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