The best place to service your foam air filter is in a workshop, not on the trail or in the pits. It is not only an extremely messy job but arguably one of the most important and must be done correctly.
Taking 2 or 3 properly oiled air filters for the ride or race will save the hassle of having to service the filter while you are out there.
Having a spare filter support frame is also a great idea. They are reasonably inexpensive, readily available and make filter changes far easier out of the workshop.
For best results use only a dedicated foam filter oil and air filter cleaner to service your filter.
There are several brands of filter cleaners and oils readily available, specifically designed for this purpose.
Avoid using engine or transmission oils on the filter as they tend to drain from the foam much faster than the tacky filter oils.
Petroleum based cleaners are not ideal for the environment or the user and may also eventually degrade the filter foam and adhesives used to bond them.
Any foam filter requires regular visual inspections to look for "dry" areas of foam or excessive dirt build-up on the filter.
Dry areas appearing on the surface of the filter is a fair indication it is due for servicing.
Dirt build-up can also restrict air flow resulting in a performance drop.
The FunnelWeb Filter is manufactured using pyramid profile foam which doubles the surface area of the filter. This allows more dirt to be trapped before drying out or loading up.
An indication the FunnelWeb Filter requires cleaning is the drying out of the peaks of the small pyramids all over its surface.
Carefully remove the filter from the airbox and shake or brush off any excess dirt from the foam.
Remove the filter from the supporting frame, pour or spray a foam filter cleaning solution onto the foam surface and massage through thoroughly until oil and dirt have been dislodged. Rinse foam in clean water and, if necessary, repeat the process.
Shake off excess water and place filter in a well-ventilated area out of direct sunlight until dry.
Dry foam will not stop dirt! A dry area as little as the size of a coin will allow dirt a virtually unrestricted path to the engine. It is therefore imperative the foam is completely oiled.
The best way to ensure the filter is properly oiled is to completely submerse the foam in filter oil and squeeze out any excess. (With its tough urethane sealing gaskets the FunnelWeb Filter can be wrung out gently without stretching the seal out of shape.)
Pour a bottle of filter oil into a good quality 4 or 5 litre container with an air tight lid.
Immerse the filter completely and squeeze any excess oil back into the container. Refit the lid and the oil is ready for the next filter service. (A 1ltr container of oil should be enough to oil approximately 10 motorcycle filters.)
Allow filter to stand for 15 minutes and then massage foam to evenly spread oil throughout.
Refit to filter supporting frame and allow to air, enabling all thinning agents in the filter oil to disperse.(Refer to oil manufacturer's instructions.)
Carefully wipe any dirt from inside of the air box where the filter seals.
Apply a layer of grease to the filter seal and refit to air box.