As far as my research goes... Yep!! Predominantly all the closed loop systems with a narrowband O2 sensor are there mainly for fuel efficiency and keeping emission norms in check. So yes, at mid range with steady rpms, the ECU checks from time to time and make adjustments whenever needed. But that doesn't mean that it will try and learn everytime you start the bike. Once it learns the parameters based on your riding habits, temperature, levity and other factors it will usually keep those values running until during one of the random checks it detects an anomaly.

Say in one of your journeys, if you do take it to a high altitude location like Leh and then witness problems with the power going down slightly, take out the terminals, wait for a bit and the put it back in.. after some time the power band will be back. Basically the residual parameters learned from the plains are wiped out and the ECU does a fresh start learning new parameters all over again. But taking such a drastic step is usually not required unless the symptoms show up.

Fuelmoto USA: Motorcycle EFI Tuning, Exhaust Components & Performance Components - Fuel Moto also sells PCV from their website but i am not sure whether they do provide custom maps and lifetime support on the same for a CBR 250R. You can shoot a mail to them and check with them to clear things out.

Instead of spending so much on a full exhaust system (stage wise) + ECU, for volumetric efficiency without losing on stock bike's reliability you may look at gas flow porting where only the flow rate of the intake and exhaust ports are increased and no other changes are made to the engine. You may notice a significant change in the powerband of your stock bike without losing on FE.

I would still suggest interact with the users who have gone for this route and have clocked significant no. of kms: they will be in a better position to give you an idea about the same.

I believe in long term test reports and would encourage everyone question things before investing.. A very wise step from your end mate

Cheers,

Hey Guys!

I have a 2012 HRC CBR250R C-ABS..

Till date, the whole bike is in Stock configuration, but now I am thinking of changing that a bit.

My air filter needs a change in near future, so I am thinning of changing it with a performance air filter so needed some advice.

I have looked and found three filters:

K&N, Green Cotton, and Pipercross.

Which one of them is best?

Also, I have heard that they let some dust pass through... is that true?
I mean, I do not want to spoil my engine or anythibg else on my beloved bike just for a decimal of HP. But wouldn't mind if it's all good.

Also, I jave heard that they increase the fuel efficiency too? So they increase Ho and FE... cake with a topping!! That's way too tasty to jump in. So needed some advice...

Thank you for the time!!!

I too have heard about dust passing through in some cases... maybe its not really worth risking the cylinder walls for a few decimals of gain... someone with long term usage of third party air filters can help hopefully. Personally I think performance air filters can be saved for track days instead of our typical dusty roads. Am too saving up for an exhaust upgrade, reduces weight and has much more significant gain in Pwr & Trq. Of course it also means significant setback financially .

Cheers.

I too have heard about dust passing through in some cases... maybe its not really worth risking the cylinder walls for a few decimals of gain... someone with long term usage of third party air filters can help hopefully. Personally I think performance air filters can be saved for track days instead of our typical dusty roads. Am too saving up for an exhaust upgrade, reduces weight and has much more significant gain in Pwr & Trq. Of course it also means significant setback financially .

Cheers.

Correct me if I'm wrong, but an after market exhaust with stock ECU would do more harm than a filter that allows dust.
With a slip on, the already lean running bike starts running ultra lean. A custom ECU would be needed.

Bottom line - stay stock and use the savings to upgrade to a bigger stock bike!

Thats true actually if you cant get a healthy map to run it on. Agree.

Is it also true on street legal exhausts?

I guess it should be true for all bikes except RE since there are many exhausts supported by OEM. Here, Honda hasn't given any *replacement* exhaust as an alternative.

Correct me if I'm wrong, but an after market exhaust with stock ECU would do more harm than a filter that allows dust.
With a slip on, the already lean running bike starts running ultra lean. A custom ECU would be needed.

Bottom line - stay stock and use the savings to upgrade to a bigger stock bike!

A slip on shouldn't make much of a difference, shiv had explained about it a few posts back. A full system at the same time would need custom mapping.

Hmm. How much gain does one see with a slip on, Akra for example?

Akra carbon fiber gives about 1bhp bump and a similar bump in the trque, the dyno chart is available in the akra site..wait a few minutes ill post it here..!!

Ok, so with a 5 kg reduction in weight + 1Nm + 1 PS increase should translate into 5-8 kmph extra right? Also, any improvement in fuel consumption documented?