Seems like many bikes are now coming with foam air filters which don't need to be replaced at every tuning.
But maintaining them in proper way is crucial to bike's engine life, so i am creating this thread for everyone to share their knowledge and tips about it.
You can also post shots from your bike manual showing how your bike manufacturer recommends it.
Here i am pasting a basic guide from Yamaha website
Step 1 - Remove the air filter from the bike, then remove the foam element from the filter guide.
Step 2 - Soak the element in clean high flash point solvent for several minutes to break down the oil then rinse in solvent to remove as much dirt as possible.
Step 3 - Squeeze out the solvent and wash the element in warm soapy water, then rinse in clean water. Squeeze out the excessive water and let the element dry. Use rubber gloves.
Step 4 - (Don't skip this step, it's the most important of all) Apply a liberal amount Yamaha foam filter oil (or whatever is recommended on the manual) to the element. Completely saturate the entire foam element, and then squeeze out the excess filter oil.
Step 5 - install the element onto the filter guide and re-install the filter assembly into the bike.
Following link also contains a very good video showing it step by step.
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