best if to use guard air filter which comes in oil as there are two types available in filter
and replace after every 5k or less then that
using original air filter makes no sense as pakistan is dusty area there you have to change filter every 5k
original one cost more then 2000 but in my view using cheap air filter for RS 400 is good and change after every 5 k
i am using in my rebirth from the very first day and i m satisfied with that
but again you have to take oil wala air filter which is not easily available
