10 Secrets Of Your Air Filter

Most of the time you don’t think about it. It doesn’t strike very many people as a performance product. It’s an afterthought when it comes to hopping-up your steed. It’s one of the cheapest parts of your $6000 bike. Yet, nothing determines whether you go or blow more than your bike’s air filter. Have you been taking good care of it?

NUMBER ONE: DO FILTERS WEAR OUT?

Yes. A filter doesn’t wear out from filtering air, but from getting cleaned between races. The harsher the cleaning solvent, the faster a filter wears out. The foam gets dry, brittle and loses the integrity of its labyrinth-like webbing.

NUMBER TWO: WHAT IS THE BEST FILTER CLEANER?

Kerosene is probably the best filter cleaner. It is the least volatile and is not as harsh on the foam. Obviously, specially made air filter cleaners do an excellent job as well.

NUMBER THREE: WHAT IS THE WORST FILTER CLEANER?

Gasoline. Gasoline breaks down the petroleum-based structure of the air filter. It ages the foam. Also bad are Snap-On or other parts cleaner solvents. They have degreasers in them that eat the filter’s glue.

NUMBER FOUR: WHAT IS THE LIFESPAN OF AN AIR FILTER?

An air filter could last forever if you never cleaned it, but your motor would probably expire in short order. A well-cared for filter will last 50 cleanings. After that many cleanings, the glue that bonds the filter pieces together gives out.

NUMBER FIVE: WHAT’S THE BIGGEST FILTER MISTAKE?

Twisting or wringing the filter to get it dry.

NUMBER SIX: IS DIRT THE WORST ENEMY OF A FILTER?

No. Water is the worst enemy. Dirt is captured in the stickiness of a well-oiled filter. Water can impregnate the oil, disperse it and allow dirt to pass through the filter. If you wash your bike with a spray washer, always re-oil your filter--even if it’s still clean.

NUMBER SEVEN: SHOULD YOU GREASE THE LIP?

If your filter has a thin base (a surface area made from compressed foam), it is wise to grease the interface between the filter and airbox. Filters that have thick foam on their base don’t need to be greased, but it doesn’t hurt. Use a waterproof grease.

NUMBER EIGHT: HOW DIRTY CAN A FILTER BE?

Sometimes you can tell by looking at a filter if it needs cleaning. The two most important things to look for are: (1) Surface area coverage. If the air filter has dirt covering every square inch of it, it needs to be cleaned. (2) Dirt depth. Even a filter that looks clean can have small particles of dirt deeply embedded in its pores. When in doubt, clean the filter.

NUMBER NINE: DO YOU HAVE TO USE SPECIAL FILTER OIL?

Yes. It is possible to use motor oil, but it’s not as good as filter oil. Motor oil is too thin and will pass through the filter and do two things: (1) It will drip out of the airbox vent onto your garage floor. This is bad because it causes a mess and because it means that your filter is no longer oiled. (2) Motor oil, because of its light viscosity, will suck into your motor when you gas it. Lots of times you see bikes that sound raspy and overly rich in the first couple of laps of practice. That is because the rider has just oiled his filter and the oil is passing through his motor.

Specially formulated filter oil has chemicals and carriers that help disperse the filter oil evenly and then evaporate.

NUMBER TEN: WHEN SHOULD YOU OIL YOUR FILTER?

It’s best to oil your filter the day before the race. That way the carriers can disperse the oil and evaporate. The MXA test crew pre-oils its filters and puts them in Zip-Loc bags (we poke holes in the bags to let air in). A pre-prepped air filter can last for months in a plastic bag.

Motocross Action Magazine

4/22/05

Thanks for passing on the info.................. :naughty:

Exellent information.

No problem guys.

air filters are so cheap anyways. i replace mine after 10 washes.

much better investment then new graphics or other non functional bling...

good info

How long is an oiled air filter good if not installed on the bike. I had a filter I had just oiled and then left it sitting on the bench for a couple weeks. I didn't put it in a baggie or anything. I got totally tied up at work for several weeks.

I could always clean it and re-oil... but just curious. It stays that way on the bike if you don't ride it for a couple weeks.

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