Bike Tuning

[IgorVigor]

Hello people.

Just wanted to share some info I found.

The best way to see how engines are running, mixture wise, is to use an exhaust gas analyser. Problem is, they arent exactly a tool everyone owns...for obvious reasons....

Well I was doing some research and found an interesting project.

make your own analyser...

All you apparently need is a mulitmeter that can read from 0.1v to 1v and get a Lambda sensor from a car exhaust.

The higher the voltage, the richer the mixture is.

Here is a basic table to work out the mixture:

Voltage: | Air/Fuel Ratio | Rich
0.97v | 12.1:1 | /\
0.88v | 12.7:1 | *
0.78v | 13.2:1 | *
0.69v | 13.8:1 | *
0.59v | 14.4:1 | *
0.49v | 14.9:1 | *
0.39v | 15.4:1 | *
0.30v | 16.0:1 | *
0.20v | 16.5:1 | \/
0.10v | 17.1:1 | Lean


The perfect air to fuel ratio is 14.7:1
so really, you would want to be aiming for 0.49~0.59v on your multimeter...

For the record, I havent tried this yet, but hopefully will when I get a Lambda sensor....could probably pick one up from a scrap yard for a couple of quid....

If anyone tries this, or already has tried it, can you tell me whether it works or worked?

Thanks for listening....(or rather reading :S)

[catteeclan]

Good idea that.
Might just have a play myself.

[Kymmy]

Nice idea except for a few things

1# What input voltage will you use for the Lamda (normally supplied via the ECU and is not normally battery voltage..could be 12v, 7v, 5v dependant on the sensor used)
2# If you get a 4 wire Lamda you'll need to wire up the heater to 13.8v, otherwise you have to let the lamda get to operation temps
3# You'll need to position the sensor near the head which would mean drilling into the downpipes and welding on a housing for it.
4# Will you use a planar or switching Lamda?
5# The figures above are for a particlar make of Lamda and not all Lamda's have the same voltage curve (should be found on the Lamda's tech sheet)

[IgorVigor]

1# What input voltage will you use for the Lamda (normally supplied via the ECU and is not normally battery voltage..could be 12v, 7v, 5v dependant on the sensor used)

You dont input a voltage to the sensor.
They work by the oxygen ions creating a small charge in the sensor layer.
Because of this, a mulitmeter can detect it and from there you can calculate the mixture...

2# If you get a 4 wire Lamda you'll need to wire up the heater to 13.8v, otherwise you have to let the lamda get to operation temps

Thats quite simple....connect the positive and negative to the battery...

3# You'll need to position the sensor near the head which would mean drilling into the downpipes and welding on a housing for it.

No you wouldnt....they only put it near the head (exhaust manifold usually) so its close to the ECU.
Exhaust gas analysers used for mots and dyno's are just a very accurate, expensive version which detects other gases...that goes in the tail pipe...

As for a housing for it, a piece of copper pipe, with a hole in the side that the sensor is silver soldered into is sufficient. This can then be either pushed into, or over the tailpipe (depending on size of tail pipe and copper pipe)

4# Will you use a planar or switching Lamda?

If by planar, you are refering to Zirconia type sensors, then yes. They create the voltage according to the amount of oxygen ions in the sensor layer.

I presume by switching sensor you mean the Titania sensor, which doesnt create a charge, rather it changes its resistance. I wouldnt use one as it would be harder to work out the values...

5# The figures above are for a particlar make of Lamda and not all Lamda's have the same voltage curve (should be found on the Lamda's tech sheet)

Most of them do produce a very similar curve. Close enough to work out how the engine is running. I believe that those exact figures are for the Bosch manufactured sensors.

I hope this clears up any confusion or problems...

EDIT: In the case of question 1, applying a voltage, even a very small one such as a multimeter's resistance setting can damage a Zirconia sensor...

Catteeclan: If you do try it, post how it went...would be interested to know what sensor you got, and whether you think it works...
I will do the same when I can get to the local scrapper and get a sensor....
Would be good if it works to compile a small list for future use of which sensors work or not....

Good luck...

[lowflyer]

Yup,

my thoughts exactly








lambda ---- Rambo the ram ? who knows

[Kymmy]

Originally Posted by IgorVigor

You dont input a voltage to the sensor.
They work by the oxygen ions creating a small charge in the sensor layer.
Because of this, a mulitmeter can detect it and from there you can calculate the mixture...

Corect as you say for a zirconia sensor but not for a titania sensor which will need a supply voltage.. hence the point was put...

Originally Posted by IgorVigor

As for a housing for it, a piece of copper pipe, with a hole in the side that the sensor is silver soldered into is sufficient. This can then be either pushed into, or over the tailpipe (depending on size of tail pipe and copper pipe)

You can't get an accurate reading in a tail pipe as the sensor needs to be in a pure exhaust enviroment (i.e. close to the head and also pre-cat for the newer bikes) Even putting it in the tailpipe your placing it near a 21% oxygen enviroment and also you're creating back pressure which will screw up the flow and reading anyway...

It's a good theory and really does need someone to go away..do a bit of research and come back to the group saying "This is what you need, this is where you can get the and this is how it's properly plumbed in" (need to do one myself as I'm switching the GPz to a megasquirt) but you do need to position them within the circuit without interferring with the fuel/air flow otherwise the results are severely tainted..

[IgorVigor]

There is enough exhaust flow even at idle to ensure the sensor reads accurately...

Granted, if your connecting it to an ECU it definately needs to be near the engine to provide the most accurate reading possible, and also so it heats up to operating temp ASAP.

It will be a negligible increase in back pressure as long as you position it correctly. I dont mean to just go and shove it in the pipe like a cork...it obviously needs a little thought, but its not hard.

Stock exhausts create a considerable amount of back pressure so the sensor probably wouldnt make much difference and in a sports can it wouldnt affect it enough to worry about.


Most of all though, I would say using it would only be a guideline....
I wouldnt recommend you tune the bike according to it only...

What I would suggest is if this works, set the jetting up according to the sensor and then do a couple of plug chops (at different points of throttle) to ensure its correct. If its pretty close, it would prove that this works quite well...

I would be happy if this could get me within a couple of jet sizes to be perfectly honest...


Any more questions, just ask...I will try and answer them...

[IgorVigor]

Been doing more research as to the wiring of the sensor.

There are 4 common wiring methods used on Lambda sensors.

1 wire, 2 wires, 3 wires and 4 wires.

The common setup for these is:

1 wire:
signal

2 wires:
signal
earth

3 wires:
signal
heater
heater

4 wires:
signal
earth
heater
heater


Any of these layouts should work for the exhaust analyser.
However, the 2 wire and 4 wire sensors would be better as the earth wire will connect to the negative side of the multimeter, giving a more accurate result.

In the case of the 1 and 3 wire types, you need to earth the unit back to the multimeter negative either through the bike frame or from the unit directly...

The heater as mentioned before just heats the sensor up to operating temp much quicker...its not absolutely required, but it makes it easier...

Good luck...

[Kymmy]

You would probably need the heated version if you are gonna put the unit in to the tailpipe as previously discussed, it would mean a much more stable reading..

PS..I moved the post to BIKE TECH as it's relevant to all models and not just the dommie..

[jasonbc]

Originally Posted by IgorVigor

Hello people.

Just wanted to share some info I found.

The best way to see how engines are running, mixture wise, is to use an exhaust gas analyser. Problem is, they arent exactly a tool everyone owns...for obvious reasons....

Well I was doing some research and found an interesting project.

make your own analyser...

All you apparently need is a mulitmeter that can read from 0.1v to 1v and get a Lambda sensor from a car exhaust.

The higher the voltage, the richer the mixture is.

Here is a basic table to work out the mixture:

Voltage: | Air/Fuel Ratio | Rich
0.97v | 12.1:1 | /\
0.88v | 12.7:1 | *
0.78v | 13.2:1 | *
0.69v | 13.8:1 | *
0.59v | 14.4:1 | *
0.49v | 14.9:1 | *
0.39v | 15.4:1 | *
0.30v | 16.0:1 | *
0.20v | 16.5:1 | \/
0.10v | 17.1:1 | Lean


The perfect air to fuel ratio is 14.7:1
so really, you would want to be aiming for 0.49~0.59v on your multimeter...

For the record, I havent tried this yet, but hopefully will when I get a Lambda sensor....could probably pick one up from a scrap yard for a couple of quid....

If anyone tries this, or already has tried it, can you tell me whether it works or worked?

Thanks for listening....(or rather reading :S)

When i had my bikes dyno'd the tuner said optimum fuelling is 13:1 then they tend togo lean in the high end of the rev range i woldn't go by that table and it doesn't tell you how accurate it would be or how to do the job and do you know what rpm it switches from slow jet to main jet??