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Discussion Starter · #1 ·
hi all

i just installed an after market airfilter (15/03/14)... got it free (swap free gift since the free riding jacket is just not my taste). I changed it on my 1000KM service
my observation on changing it (this 2-3 days)... engine kinda lean, pick up feels better (i think) but my top speed suffered.

am i doing it wrong? i did read that should i actually do a dyno and reprogram the ecu since the Air–fuel ratio (AFR) has significantly changed? is this true?

any comments? gonna change back to stock air filter tonight.


product website
BMC FM733/20
 

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I don't think the stock ECU and Lamba sensor are any good at dealing with ranges outside a very narrow band. I'm probably going back to the stock pipe as well for the same reason.
 

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this is just what i think but im not sure if an air filter will be able to change the flow characteristics enough to negatively effect the A/F ratio
 

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this is just what i think but im not sure if an air filter will be able to change the flow characteristics enough to negatively effect the A/F ratio
Yeah I doubt the filter alone could do that, you need to alter the whole air intake setup to have it make a big difference with flow
 

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Discussion Starter · #6 ·
well maybe its just me ....but after going back to stock i feel the bike is back to its original performance
i think the airfilter will only be useful in the future when i get myself a powertronic
 

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From what we've tested, you gain 1hp at the wheels throughout the powerband with this filter on the Ktm 390 (You would gain with any other brand too; it just so happens that we tested this brand in particular)

Go ahead with it, you will feel a difference even on the stock ecu.
 

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Im still waiting for my pipe to arrive :mad: but once it does Im expecting both filter and pipe should keep everything in balance.
Does anyone know if the 15 min idle reset thats performed on the 690 after Lambda changes works on the 390? Should this been done/tried with the PowerTRONIC?

Pics of the DNA Filter "MASS AIR" :D



 

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Havent done it yet but its straight forward, pop the seat, unscrew and drop in. Gotta oil 1st as per usual.
The flow rates are much greater, Im really looking forward to dropping it in but not sure if I should wait for the Powercone to arrive first. Im dumping a lot more air in there and with the PowerTRONIC it may help a lot or not so im still unsure, bit more questioning to do. The RD guys are doing maps atm so with all 3 together and shop tune im expecting some positive results.

Has anyone seen flow rates for the K&N filter? I havent dug very deep but it would be interesting to compare it to the stock one. I remember being shown a filter for a GSX-R 600 from K&N against the OEM one. Weirdly the K&N was more restrictive than the OEM.
 
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