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Discussion Starter #1
Did a complete dyno test run on my 06 K12S with 7.0 SW.

(146,6 [email protected] at the rear).

The CO, CO2, O2 and HC values (from the exhaust) was interesting (at least for me).

I just want to share this with you.

CO = 2 - 4% (normal/typical: 5 - 7%) - the purple line
CO2 = 11 - 13% (normal/typical: 10 - 11,5%) - the green line
O2= 1 - 2% (normal/typical: 0,8 - 1,1 %) - the blue line
HC = 20 - 50 ppm (normaltypical 600 - 1200 ppm) - the yellow line

The conclusion is that this bike is running EXTREMELY lean and clean. Normally the HC value (i.e. unburned fuel) should be 600 - 1200 ppm. Lower values will normally make the exhaust too hot. The guy that did the test has never seen such low HC values.

The high O2 values indicate that the engine could burn more fuel (and create more hp). The high CO2 and low CO indicate a very very effective combustion.

This beast could easily create more hp just by adding a little more fuel. This engine is screaming for more fuel ;-)
 

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cat converter?

Is this with a Cat.- stock muffler or slipon or whole new system??
H



ratemut said:
Did a complete dyno test run on my 06 K12S with 7.0 SW.

(146,6 [email protected] at the rear).

The CO, CO2, O2 and HC values (from the exhaust) was interesting (at least for me).

I just want to share this with you.

CO = 2 - 4% (normal/typical: 5 - 7%) - the purple line
CO2 = 11 - 13% (normal/typical: 10 - 11,5%) - the green line
O2= 1 - 2% (normal/typical: 0,8 - 1,1 %) - the blue line
HC = 20 - 50 ppm (normaltypical 600 - 1200 ppm) - the yellow line

The conclusion is that this bike is running EXTREMELY lean and clean. Normally the HC value (i.e. unburned fuel) should be 600 - 1200 ppm. Lower values will normally make the exhaust too hot. The guy that did the test has never seen such low HC values.

The high O2 values indicate that the engine could burn more fuel (and create more hp). The high CO2 and low CO indicate a very very effective combustion.

This beast could easily create more hp just by adding a little more fuel. This engine is screaming for more fuel ;-)
 

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This is why I hesitate to throw an aftermarket exhaust and open up the airbox(on my R). With more air coming in and going out, the engine will lean out even more. Too much and that means rapid valve guide wear and burnt exhaust valves.
I'm not the only one that thinks this either. I've heard (second hand, of course) of K12S/R owner requiring a $5000 valve job after simple mods posted here caused the exhaust valves to erode.
I wonder if some driveability problems are actually burnt exhaust valves?
A leak-down test would be a good test for the valves.
 

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JCW said:
This is why I hesitate to throw an aftermarket exhaust and open up the airbox(on my R). With more air coming in and going out, the engine will lean out even more.
I remember it was you who said a posssible answer would be disconnect the 02 sensor to richen up the mixture. Makes sense to me.

I am still happy to say my 05 S is running most excellent after a combination of 3 mods. Akropovic full system, Evoluzione filters and removal of 02 sensor. I still have 6.0 installed. When new, the bike ran poorly. 6.0 helped somewhat but the pipe, filters and 02 removal seemed to be the cure for mine.

Time will tell.
 

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Discussion Starter #6
JCW said:
This is why I hesitate to throw an aftermarket exhaust and open up the airbox(on my R). With more air coming in and going out, the engine will lean out even more. Too much and that means rapid valve guide wear and burnt exhaust valves.
I'm not the only one that thinks this either. I've heard (second hand, of course) of K12S/R owner requiring a $5000 valve job after simple mods posted here caused the exhaust valves to erode.
I wonder if some driveability problems are actually burnt exhaust valves?
A leak-down test would be a good test for the valves.
I agree.

An aftermarked chip (powercommander) that could increase the fuel-to-air ratio would be better.
 

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JCW said:
I've heard (second hand, of course) of K12S/R owner requiring a $5000 valve job after simple mods posted here caused the exhaust valves to erode.
I find it hard to beleive that a pipe and filter would destroy a motor. This is probably the first change made to most bikes and we'd be hearing of a lot more problems.
 

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Probably won't happen to most people. But someone that's always on the loud pedal, redlining the bike constantly, and a bad tank of gas...
then a bike that is bulletproof may explode. Maybe.
 

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ratemut said:
...................The CO, CO2, O2 and HC values (from the exhaust) was interesting (at least for me).

CO = 2 - 4% (normal/typical: 5 - 7%) - the purple line
CO2 = 11 - 13% (normal/typical: 10 - 11,5%) - the green line
O2= 1 - 2% (normal/typical: 0,8 - 1,1 %) - the blue line
HC = 20 - 50 ppm (normaltypical 600 - 1200 ppm) - the yellow line.................
Interesting results but I have to ask, at what point in the exhaust system was the gas analysis taken. I understand that the analysis is highly altered by the catalytic converter so simply testing at a point after the cat is not useful. An overall assessment of emissions and A/F ratios can be made from gas analysis at the header collector and an individual cylinder assessment taken from each exhaust header upstream of the collector. If there is another viable approach to this I'm interested to hear it.
 

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you are correct Lenz.

The job of the cat is to vaporize. any unburned emissions. It is afterall a furnance. Thats why it retains its heat so long. Removing the stock exhaust and adding a air filter system would not ruin the engine IMHO . The heated O2 sensor would make sure the air to fuel mixture would remain in the correct ratio of 14.5 to 1 air to fuel ratio. I don't beleive remapping the fuel mixture would help as it is at its optimum at this setting. changing the exhaust and airfilter system would increase the HP as the faster the air can get in and out of the engine the better. Now everyone knows why there are snorkel air intakes pointing foward in the airstream . At speed they slightly pressurize the airbox increasing the airflow in and out of the engine. The new k1200's are quite a masterpiece of engineering.
 

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Discussion Starter #11
Lenz said:
Interesting results but I have to ask, at what point in the exhaust system was the gas analysis taken. I understand that the analysis is highly altered by the catalytic converter so simply testing at a point after the cat is not useful. An overall assessment of emissions and A/F ratios can be made from gas analysis at the header collector and an individual cylinder assessment taken from each exhaust header upstream of the collector. If there is another viable approach to this I'm interested to hear it.

That's a good question. Maybe the low HC value are a result of the cat ??

I think the analysis was taken aprox 10 inch down in the pipe. I guess that is after the cat ??
 

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tonysrep said:
The job of the cat is to vaporize. any unburned emissions. It is afterall a furnance. Thats why it retains its heat so long. Removing the stock exhaust and adding a air filter system would not ruin the engine IMHO . The heated O2 sensor would make sure the air to fuel mixture would remain in the correct ratio of 14.5 to 1 air to fuel ratio. I don't beleive remapping the fuel mixture would help as it is at its optimum at this setting. changing the exhaust and airfilter system would increase the HP as the faster the air can get in and out of the engine the better. Now everyone knows why there are snorkel air intakes pointing foward in the airstream . At speed they slightly pressurize the airbox increasing the airflow in and out of the engine. The new k1200's are quite a masterpiece of engineering.
The correct A/F ratio for most power on gas (vs methanol) is ~12.5:1, not 14.7:1.
The O2 sensor does not function in WOT mode as it is inaccurate at lower air fuel raios.
How do you know the map is at the optimum setting? Optimum for what? Power, fuel economy, for premium gas, for something less than premium?
If it is at optimum setting, adding more air by mods would take it out of optimum setting, correct? If you've every worked on carbs, a air filter kit most times required a new jet kit as well. Same with fuel injection. The computer cannot change WOT values via the O2 sensor.
 

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Not familar with the o2 sensor removal mod - what does it do? What are the pros and cons please? Thanks...did you do all 3 at once or in stages? How do I remove it?
 

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sportrider said:
Not familar with the o2 sensor removal mod - what does it do? What are the pros and cons please? Thanks...did you do all 3 at once or in stages? How do I remove it?
This is my experience only.

My bike had 5.0 when new. Ran like crap. Typical slow speed driveability problems we are so familiar with. I put on a Remus end can with Evoluzione filters. No improvement. Since that was the case, I removed the filters because I thought they were too loud.

Had the 6.0 installed, better but still some of the same problems.

Installed the Akropovic full system and put the filters back in. Removed snorkels of course.

Since the Akrapovic comes with an 02 sensor plug that is saftey wired in place, I decided to try it that way. 02 will disconnect under your gas tank. Pull off the plastic panels, raise the gas tank (not necessary to disconnect the fuel lines). The 02 sensor will disconnect and your done.

My bike is now running so well that I opted to NOT install 7.0 when the bike was in for 6k service on Saturday.

I think it's worth a try on any bike that has the catalytic converter removed. BTW, there is a more complete recent thread on this subject in the k1200r section.

Good luck.
 

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JCW said:
The correct A/F ratio for most power on gas (vs methanol) is ~12.5:1, not 14.7:1.
The O2 sensor does not function in WOT mode as it is inaccurate at lower air fuel raios.
How do you know the map is at the optimum setting? Optimum for what? Power, fuel economy, for premium gas, for something less than premium?
If it is at optimum setting, adding more air by mods would take it out of optimum setting, correct? If you've every worked on carbs, a air filter kit most times required a new jet kit as well. Same with fuel injection. The computer cannot change WOT values via the O2 sensor.
You are incorrect on this one sir , 14.5 to 1 is the optimim ratio , most vehicles today (cars) run at 16.7 to 1 (According to my 5 gas analizer )for the fuel mileage but at a cost of power. At 12.5 the vehicle would load up and fowl the plugs as it it way too rich unless the throttle is wide open. I recently played with my old gs750 (rejetting the carbs ) , at 13,8 to 1 it was fowling the plugs .
 

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tonysrep said:
You are incorrect on this one sir , 14.5 to 1 is the optimim ratio , most vehicles today (cars) run at 16.7 to 1 (According to my 5 gas analizer )for the fuel mileage but at a cost of power. At 12.5 the vehicle would load up and fowl the plugs as it it way too rich unless the throttle is wide open. I recently played with my old gs750 (rejetting the carbs ) , at 13,8 to 1 it was fowling the plugs .
How am I incorrect? I stated for best power A/F ratios are ~12.5:1. Best power means wide open throttle.
Of course, at idle a lean mixture is more efficient. But I for one don't tune engines for a fantastic idle and emissions(edit- I'll let the factory do that)... I tune for WOT power.
You sir are incorrect stating that the remapping won't help. If you increase airflow, you have to increase fuel. The O2 sensor won't do this at anything above light throttle.
Listen, I don't mean to insult you, but before you spout out numbers you should look at some facts. ANYONE who's tuned an engine on a dyno knows that best power is made at ratios richer than 14.5:1.

http://en.wikipedia.org/wiki/Air-fuel_ratio
(Look under AFR about 3 sections down)

Edit- Let's take this to the extreme. Let's say you put a turbocharger or supercharger on an engine. Basically both operate by allowing more air to get into the engine. Are you saying that if you have an O2 sensor you don't have to adjust fuel maps? Of course you do.
 

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JCW said:
...The computer cannot change WOT values via the O2 sensor.
You're right the O2 sensor supposedly doesn't work above about 15% throttle. It's used for light throttle emissions reasons, not heavy throttle performance optimization.

Does the K1200S have a Mass Airflow Sensor, or any other way to determine airflow has increased? If so it could theoretically increase injection duty cycle to maintain proper A/F ratio.
 

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xlr8r said:
...Installed the Akropovic full system and put the filters back in. Removed snorkels of course...Since the Akrapovic comes with an 02 sensor plug that is saftey wired in place, I decided to try it that way. ...My bike is now running so well that I opted to NOT install 7.0 when the bike was in for 6k service on Saturday...
I put the full Akropovic system and Evo air intake on my '06 K1200S running 7.0. I initially didn't connect the O2 sensor, as described above. After about 100 miles it developed a consistent high-rpm misfire (above 8000 rpm in 2nd gear) at WOT. I put the O2 sensor back in; no difference. Still misfires. Currently at BMW dealer for diagnosis.

Don't know if this is a 1-off problem or combination of 7.0 and aftermarket exhaust and intake. I'm sure very few people are running both 7.0 and aftermarket intake/full exhaust system.

If the dealer can't resolve this, I already have the Dimsport RapidBike3 unit and a local performance shop will use that and try to tune out the problem, verifying A/F ratio is appropriate.
 

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o2 senser

I am not too sure about the bike, but on a BMW car if you disconnect the senser the engine goes into "limp home mode", doesn't run very well and sets a fault code. They have done this for years.
H



xlr8r said:
I remember it was you who said a posssible answer would be disconnect the 02 sensor to richen up the mixture. Makes sense to me.

I am still happy to say my 05 S is running most excellent after a combination of 3 mods. Akropovic full system, Evoluzione filters and removal of 02 sensor. I still have 6.0 installed. When new, the bike ran poorly. 6.0 helped somewhat but the pipe, filters and 02 removal seemed to be the cure for mine.

Time will tell.
 

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joema said:
...............I already have the Dimsport RapidBike3 unit and a local performance shop will use that and try to tune out the problem, verifying A/F ratio is appropriate.
As I've said on a number of posts, I believe BMW are seriously constrained by emission control regulations and apparently no amount of griping is gonna see BMW release an "off road" map that will have the bike run to its potential without regard for the emission standards. If you're not satisfied with the way the bike runs now, even after 7.0, the only option that I see is to do as so many other bike owners of all makes and models have done and install an aftermarket engine management system with supplied or custom mapping.

Joema, have you considered any of the available maps from the Dimsport organisation or from Ken at Evoluzione. Even if the available maps are not an optimum match, they could provide a close start point for the guys who are going to fine tune the unit to the bike. I'm genuinely glad to see someone on this forum has opted to move past BMW's constrained mapping options - Unchain the beast!
 
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