Thread: Bike India Q&A - R15 Aftermarket Airfilter

I want to bring attention to the Q&A section in Bike India January 2009 edition. The first question is asked by someone wanting to fit a K&N airfilter to his R15. He was concerned if the bike would need re-jetting since it is fuel injected.

Bike India's response:- Yes, you can fit a K&N filter on the R15. The ECU of a fuel injection system will automatically alter the fuel flow to suit the free flow filter.

The above answer is INCORRECT. The R15 fuel injection system will NOT adjust the fuel flow automatically because it runs an open loop fuel injection system. There is no O2 sensor providing feedback to the ECU on whether the bike is running rich or lean. On the R15, the airfuel ratio needs to be set manually with a handheld controller available for the purpose. Open loop FI systems are used on small bikes like the r15 to save costs. There are also closed loop FI systems such as those used in cars and they are quite expensive. A closed loop system is capable of making adjustments to the fuel flow based on inputs from various sensors in the vehicle.

Magazines should be 100% sure before publishing such info to the masses. If anyone here can convey this to the right people in Bike India, please do.

Topic Approved

Just saw the email address and i've emailed them as well

Hopefully its corrected in the next issue. We dont want people running around fitting K&N's thinking the bike will automatically adapt. The R15 will inevitably run lean with a K&N filter until the AF ratio is corrected manually. This is also probably something you dont want to encourage either because most of the yamaha showrooms either dont have the handheld tuning unit or dont know how to use it

These Mags are just .....

Be it any . they just want to fill pages.

@Killer
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Originally Posted by Killer

Just saw the email address and i've emailed them as well

Hopefully its corrected in the next issue. We dont want people running around fitting K&N's thinking the bike will automatically adapt. The R15 will inevitably run lean with a K&N filter until the AF ratio is corrected manually. This is also probably something you dont want to encourage either because most of the yamaha showrooms either dont have the handheld tuning unit or dont know how to use it

Good that you have made the R15 owners aware. A lot of youngsters buy this magazine and follow the advice given. You might want to send a PM to Bunny.

well bike India does have some errors every now and then but this would be damaging as a lot of readers do buy this mag and would follow it.

but the damage would be done already as the person who queried probably has already fitted the filter on his R15.

and also error rectification published in a mag are USUALLY very small in print and not noticeable. its should at least eye catching so as to seriously rectify the damage caused.

OT
Btw a question that triggered by reading this.

since the R15 have a open loop ECU
then wouldn't the bike have serious problem operating at higher altitudes ? because it'd need more VOLUME of air (since the density decreases) in order to burn the same fuel.

Many went for K&N either only for sound or in expectation of more performance without knowing anything at all about what makes the bike give better performance with a K&N... But then, a louder bike sounds to be performing better!

So, the R15 is on an open loop FI system like the RTR... thought this one is a full fledged system. How about the P220's FI? Is that too the same?

Open loop Fi;; Damn Thats the culprit...
Damn--Cost Cutting even here....

thats y i always wondered when im in blr , the bike struggles to move , Same set up in chennai/AP/mangalore/kerala(where all iv taken it) anywhere its hot , the bike moves with ease.
damn i cant keep tuning it with everychange in temp or place that i go to.
then whats the help of Fi other than better metering ??

@Killer
Pls explain my doubt ...


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Originally Posted by Xenologik

since the R15 have a open loop ECU
then wouldn't the bike have serious problem operating at higher altitudes ? because it'd need more VOLUME of air (since the density decreases) in order to burn the same fuel.

P220 does have an air temprature sensor that alter the supply of the air according to the prevailing air temprature. That is the one reason that in recent Himalyan ride of Bunny, p220 was the only bike which managed to reach the highest point without any hiccups.

I have nothing against the mag, just pointing out an error.

The internal workings of these ECU's are fairly complex and i'm no expert on the subject but from what basic knowledge i do have of open loop systems they have inbuilt maps for different conditions the bike could possibly be in. There are various other sensors that provide input to the ECU. MAP or Manifold Absolute Pressure sensors are used guage atmospheric conditions. They are generally located in the intake manifold, i havent verified if the R15 has one though. What i am sure of is that there is no O2 (lambda sensor) and without that the air fuel ratio cannot be automatically managed.