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Discussion Starter · #1 · (Edited)
I have my bike partially debaffled and am not likely to go for custom pipes at this stage because the bike is loud enough! I am contemplating a Baron Big Air Kit on the bike.

My question is what will this mean for fuel/air ratios? Will I need to do some fuel retuning and time on a dyno? If that is the case, is it potentially worth going for something like a Cobra FI2000 PowerPro Tuner rather than spend on dyno time and retuning?
 

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I am glad to share my experience with you of tuning my 1700, involving the Cobra 2000r. There are hundreds of opinions on tuning and someone will no doubt disagree with mine, all I can do is offer the information and leave you to arrive at your own decision.

Unless I am mistaken the Australian market version of your bike runs an O2 sensor, same as the European versions. This is the first problem, as the Cobra tuners are not designed for use with the O2 sensor bikes. I spoke to the tech at Cobra in great detail about this. The best, but not perfect solution is to run an O2 eliminator when using the Cobra tuner.

Any changes to the restriction of gas flow in the exhaust or inlet will result in a change in fuel ratio. Especially if you change the inlet side. This doesn't mean you can ignore changes made just to the exhaust as it runs lean in the stock setting, so allowing more air flow will lean it down even further.

The Cobra tuner I used for a short while on my bike made the fuelling terrible, with on/off throttle hesitation, reminiscent of the early fuel injection systems, no doubt due to the piggy back set up. The best way to go is to have the standard ECU re-mapped, and there are a few companies that are now offering a re-map service, which started in the car tuning world, and is starting to filter through to bikes. The ZX10R is a popular model that tuning companies advertise the remap service for, and other Kawasaki models are being added all the time, thus negating the need for a plug in tuner.

A simple fix for now would simply to be to run an O2 eliminator, which richens the mixture up nicely, and may add enough fuel to cover your exhaust mods.
If you go for the inlet mods you will need some form of remap, I would go for a PCV if you are unable to get the ECU modified, and some dyno time to get it perfect.
 

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None. Your bike should run fine as long as you do not change the pipes. The BAK looks awesome and you will get a little more growl from the engine area :)

(Personal experience with my 09 900)

P.S. If you plan on future mods (pipes) I would advise investing in the Cobra PowerPro auto tuner. It works very well and will automatically adjust the air/fuel ratio for max power.
 

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Discussion Starter · #4 ·
Tuning is a complete mystery to me at this stage. I kinda get the principles but there's so much I don't get yet!
 

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Tuning is a complete mystery to me at this stage. I kinda get the principles but there's so much I don't get yet!
Whilst I do not know everything about tuning the principles are quiet simple.

The problem with modern engines is that the laws of emission, and noise are in direct conflict with the laws of tuning for best engine performance and longevity.

For an engine to pass emissions laws it has to run clean and quiet. Looking at the clean part first, ignoring the fresh air systems that draw in clean air to help fool the emission test, it means that we want the cleanest most efficient burn so that all the fuel is consumed and the minimum amount of nasty pollutants come out of the exhaust. The fuel ratio that achieves this is known as the stoichiometric air fuel ratio, which is about 15:1. 15 parts air 1 part fuel. Unfortunately, this clean burn also means a hot burn, and it also is not the best for power. The peak power is achieved around 14:1 or even lower 13.5:1. The extra fuel also cools the combustion chamber resulting in a cooler running engine.

As for the noise, restrictive exhausts and inlets are used to help keep the exhaust noise and inlet noise to a minimum, unfortunately this also means bad news for the engine, as it struggles to suck in fresh air. The less air we have, means the less fuel we can have, which means less power, then all the gases have to get out, and if they are restricted by a quiet exhaust, that means the engine can't get rid of the hot gases, which means again, less power and more heat.

So if we look at a stock engine, first off at cruise or slightly open throttle it is running in closed loop, which means the O2 sensors are dictating the AFR, which is set to run at stoichiometric for a clean burn to get through the emissions, which are tested at cruise, and slight acceleration. Only when you accelerate hard will the engine ECU look at the fuel tables and add fuel according to all it's other sensors, and run in open loop allowing a better fuel ratio. Most of the time its running in closed loop or lean.

Now add a free flowing air filter, and free flowing exhaust, and you have an engine that can breath, but requires more fuel. The fuel tables that the ECU uses for hard acceleration are not affected by the O2 sensor, so the ECU will continue to add only enough fuel for a standard engine, so it will run lean and hot.
The narrow band O2 sensors only work over a narrow AFR, and can't compensate for major changes in the state of an engine tune, so you'll run lean at cruise as well.

There are many options, including installing wide band O2 sensors as used with the Auto Tune devices, but from my experience and countless hours talking to tuners at raceways and tuning shops, the best way to tune an engine is on a dyno so you can remap the engine's ECU, or instal the industry standard tuning device which is the PCV.

The Harley system is great because you can just flash the ECU for whatever pipes and filter you have fitted.
I run a standard Voyager, with just an O2 eliminator, which means whenever the engine is in closed loop, looking for the O2 sensor to provide feedback on how the AFR is, the eliminator sets the AFR to 14:1 which is just enough to get rid of the rough running and flat spots, and keep things a little cooler. In fact, my main aim was a cooler running engine, and a set of slip on silencers and tuner from Cobra didn't keep the engine any cooler than just running the O2 eliminator with the rest standard, which tends to suggest the standard settings on the tuner were a bit off, giving another example of why you need to put your bike on a dyno to get it perfect. Dyno time isn't that expensive, certainly not as costly as a hole in you piston from running lean.

Hope this helps you understand a bit more, and for those that wish to pick holes in what I've said, yes, this is a very simplified version because that's all I can cope with ha ha.
 

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Romper,

Well, the Cobra is pure plug and play. There are no O2 sensors to weld in, maps to download, no dyno time. It actually adjusts fuel air mixture for max power no matter what set-up you have, or what elevation you ride to.

I used to move pipes and air cleaners on and off my 900 just to tinker. No need to change map. The Cobra automatically adjusted for the set up at the time. I rode it from Texas through the Rockies from Colorado, Wyoming, Montana and Idaho and back. The Cobra adjusted for elevation automatically.

I didn't have to do anything other than hook it up and ride. And, it made a very nice difference in performance. The Cobra Auto-tune model was worth every penny I paid for it. I would buy another one in a heartbeat.
 

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Discussion Starter · #8 ·

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There are some differences between these tuning modules, it goes something like this;

The Fi2000r, (not the auto tune) modifies the original fuel map from the standard ECU, by adding a longer pulse at the fuel injector. This means that you are still limited to the original fuel curve, you just get to add more fuel along the way, although you can to a certain extent, by adjusting the three tuning pots within the device, adjust how the fuel is added, in a similar way to adjusting jet size, needle height and mixture screw on a carburettor, but you are still tied to the basic fuel map. With an O2 sensor bike, it gets more tricky because when running in closed loop mode the O2 eliminators will already be fooling the ECU into adding more fuel, and then the Cobra is going to be doing the same thing. If you leave the original O2 sensors in place then they will be telling the ECU to add less fuel because the Cobra is making the AFR too rich for the emissions settings that the O2 sensor is there to keep an eye on.

The Auto tune Cobra and Power Commander, are basically running in closed loop, with the Wide Band O2 sensor set to tell the Cobra or PC module to adjust according to what it is detecting. These work, but can have problems, according to the Tuning Shop near me that runs the Kawasaki British Superbike Team. They have hundreds of hours of Dyno experience, tuning not only the Kawasaki team bikes, but also many other teams from British and World Championships. They said they don't always respond correctly to what the throttle and engine are doing, and can be very glitchy.

The standard PCV module is the most tunable. It allows the fuel map to be corrected every 100 revs throughout the rev range. So for every 1000rpm increase you get 10 adjustments. This allows very accurate tuning. The bike will still adjust itself for changes in altitude and temperature etc, but the fuel map will be as close to perfect as possible if set up on a dyno. If you can't get to a dyno you can download a specific map from the manufacturers website for your model bike with the specific pipes/filters you have fitted.

Unfortunately it is a sign of the times we live in that lean burn engines and ever more restrictive legislation is set to kill the internal combustion engine. Here in the UK a campaign group recently just managed to stop a law that would have made it illegal to alter any motorcycle from standard.
 

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thanks.

sorry of being a bit ignorant, but why did you choose the cobra auto tune unit over the PCV autotune unit?

I don't think I got it or observed the answer in your last post....


Romper
 
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