CO adjustment question

[abraxas]

So after a few repairs and adjustments, i'm not getting great fuel consumption. Now this could be a number of things, if you guys could just double my thinking on this? I ride a fair mix of high speed and slow, so it's a very all round average figure.

From the start i was getting 22km/L, as measured each time i filled up. So if i got 260km on the clock, i'd fill up with say just under 13 L. Now i get (this morning) 240 km, but 14 L.

It could be a few things:
1. Sprocket: have a -2 back sprocket fitted, so COULD be under reading milage, ie no problem.
2. I'm getting popping at low revs when coasting, here's my clue it's fuel related. Just light popping, nothing much.
3. Idling is set low, throttle 100% accurate, and engine is running smoothly.
4. Almost imperceptable drag on the bike when releasing throttle, very slight, could just be me.

SO of the various thoughts, the CO is the easiest to adjust, they're both on 0 right now. What i don't know is how to judge whether to increase or decrease?

 

[krid80]

Is the bike stock?

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[Motogiro]

So after a few repairs and adjustments, i'm not getting great fuel consumption. Now this could be a number of things, if you guys could just double my thinking on this? I ride a fair mix of high speed and slow, so it's a very all round average figure.

From the start i was getting 22km/L, as measured each time i filled up. So if i got 260km on the clock, i'd fill up with say just under 13 L. Now i get (this morning) 240 km, but 14 L.

It could be a few things:
1. Sprocket: have a -2 back sprocket fitted, so COULD be under reading milage, ie no problem.
2. I'm getting popping at low revs when coasting, here's my clue it's fuel related. Just light popping, nothing much.
3. Idling is set low, throttle 100% accurate, and engine is running smoothly.
4. Almost imperceptable drag on the bike when releasing throttle, very slight, could just be me.

SO of the various thoughts, the CO is the easiest to adjust, they're both on 0 right now. What i don't know is how to judge whether to increase or decrease?

The only way I know is with a sniffer. You should be watching your air to fuel ratio. That way regardless of modification you can see what's actually occurring. The other way your guessing.

Do you have an aftermarket exhaust? A lot of people notice D'cell popping after they get a new exhaust. The D'cell pop was always there with the stock system but not noticeable until the exhaust was louder.

 

[MagicMANX]

When I got my bike, it has the CO setting in -20 and -10, I adjusted it to -10 and -5 just a bit more fuel, the mixture was very lean, and making the engine very hot, I drive a lot of street/city so a lot of start and stops.

With that setting, fuel consumption went up, from an average of 22km/l with -20 and -10, to average 19km/l with -10 and -5, so based on that I pressume that you will get even lower km/l based on your setting and the new sprocket.

Cheers

 

[Motogiro]

When I got my bike, it has the CO setting in -20 and -10, I adjusted it to -10 and -5 just a bit more fuel, the mixture was very lean, and making the engine very hot, I drive a lot of street/city so a lot of start and stops.

With that setting, fuel consumption went up, from an average of 22km/l with -20 and -10, to average 19km/l with -10 and -5, so based on that I pressume that you will get even lower km/l based on your setting and the new sprocket.

Cheers

If you leaned out your mix (less fuel more O2) with a higher head temperature, why did your fuel consumption go up?

The higher temperature is why I like to see actual air:fuel ratios from a probe.
I'm thinking those adjustments were designed with the concept of a measuring device that tells you the result of your adjustment.:Flash:

 

[MagicMANX]

If you leaned out your mix (less fuel more O2) with a higher head temperature, why did your fuel consumption go up?

The higher temperature is why I like to see actual air:fuel ratios from a probe.
I'm thinking those adjustments were designed with the concept of a measuring device that tells you the result of your adjustment.:Flash:

What I ment was:

Before -20 -10 lean mixture, hot engine, low fuel consumption
Now -10 -5 bit more rich mixture, bit cooler engine, bit higher fuel consumption

Cheers!

 

[abraxas]

Ok thanks guys, bike 100% stock, including exhaust.

MagicManx, why are your ratios different? ie -20 -10, should they not be the same?

I'm scared of leaning it out too much, ie at all. Where could i get a "sniffer" to measure the co in the exhaust? I wonder if yamaha has one .... they don't, some guy broke it ...

Apparently it can only be done via a dyno tune though, which i distrust, generally, because of what it MAY do to the inside of my engine. Thoughts?

 

[MagicMANX]

The CO settings are different because of the way the injectors work

CO -20 is for the outside cylinders, they can go very lean because of the position, they receive a lot of air, so they can run a little hotter

CO -10 is for the inside cylinders, as they are caged in the middle of the engine, they should run a little richer, as the extra fuel will help cool down the cylinder.

My engine was running pretty hot in start/stop traffic, thats why I changed the setting to be richer in both outside and inside cylinders.

The fz6 has "shared" injectors, CO 0 is for cylinders 1 and 4, and CO 1 is for cylinders 2 and 3.

Hope this information helps you ! Got it from this same forum, just search for "CO setting"