Air Filter

I have put more than 20000 km on my current air filter, now apart the grey colour it seems clean and perfect, also airbox interior is clean and the bike run fine.

Schedule tell me to change it very soon...what are the risks of putting others 5000 km on it?

Ciao

Risk is minimal. I run air filters a lot longer than that although I do not ride in a particularly dusty environment. I would simply use an air hose and blow out any loose dust and re-install it for another 20,000 + kilometers. If it was very dirty or if you ride in a dirty environment, I might consider changing it but it probably is not necessary.

The grey colour is probably due to car smog, I live in a very polluted area

There was no picture of your air filter but I have found the filter seems to get dirty on about 1/2 the element. I use an air hose to blow off the dirt and reinstall reversing the dirty side. After about 20,000 miles I replace the filter as it gets pollutants in the element that cannot be removed with compressed air.

No risk. "Dirty" air filter does not let dirt in, just doesn't let air in.

Wait - you're supposed to change them?? I guess I better figure out where the darn thing is. But it may not be due yet - I only have 130,200 miles on the bike. Maybe the previous owner put a new one in while he had it. I got it at 40,000 miles.

so u never change it?

As has been noted, a dirty filter won't let dirt in, it will eventually restrict air flow. Bearing in mind the surface area is designed to flow sufficient air at the end of life for a motor at full RPM, seems pretty likely it will be difficult to feel a difference if you don't run around at high rpm and speed.

Being the inquisitive type, it would be interesting to use some kind of flow meter to to test an air filter over time (say every 10 k miles) to see how much efficiency you're losing as it gets dirty. Of course a back to back dyno run with a new filter and one with 50K miles on it could be revealing too.

Of course mileage alone is only one factor in how fast a filter gets dirty.

Holy cow. Is $20 for a freaking air filter all that much to spend? Making a list of who not to buy any bikes from!

Yamaha says to change it more often in wet conditions. Why? Does moisture damage the paper filter element letting stuff through? Or something else? I always wondered about that........

Maybe moisture makes it collect more dirt, so you get dried mud on the filter?

900gc said:

Being the inquisitive type, it would be interesting to use some kind of flow meter to to test an air filter over time (say every 10 k miles) to see how much efficiency you're losing as it gets dirty. Of course a back to back dyno run with a new filter and one with 50K miles on it could be revealing too.

Click to expand...

Have only seen them on diesel pickup trucks but my F-250 had such a gauge on the airbox. Check at idle for restriction indicating time to change. Also electric sensor to alert the driver who never opens the hood.

A shop vacuum cleaner and vacuum gauge could be used to compare one filter to another. Once found a page online where a group of Japanese street racers decided to answer the question as to which filter filters best for least restriction. They used a shop vac, vacuum gauge, and printer toner for their tests. A second "filter" of white cloth was used to see how much toner passed. The K&N was poorest at filtering.

I threw away the stock air filter and replaced it with a washable K&N.

K&N?

https://www.nicoclub.com/archives/kn-vs-oem-filter.html

Lots of info out there that although the K&N may flow a bit better, it does so at the expense of adequate filtration. The link I posted is just one example.

The OEM filter will not limit performance by not moving enough air. I seriously doubt you could measure any difference - even at high RPM on a dyno.

RossKean said:

K&N?
https://www.nicoclub.com/archives/kn-vs-oem-filter.html

Lots of info out there that although the K&N may flow a bit better, it does so at the expense of adequate filtration. The link I posted is just one example.

The OEM filter will not limit performance by not moving enough air. I seriously doubt you could measure any difference - even at high RPM on a dyno.

Click to expand...

I haven't gone back and look at the threads, but I think that (Uselesspickles maybe?) in all his air box modding trials and dyno runs ended up staying with the OEM filter as the best option for both filtering and performance.

I just want to know what a kilometer is, is it like a 5 day weekend or something.

I think it has to do with mountain climing. Several have died trying to conquer Mt Killometer. 8O)

Sounds pretty cut and dry to me, clean is clean. Save yourself some $$$$$$

The dangers of using an air filter for too long are very small. If the air filter becomes overly dirty and begins to restrict air flow, this would be a problem when the engine is pumping maximum air volume, in other words only at WOT at redline, and decreasing importance as these factors are lessened.

In the situation where the filter is restricting airflow, the Intake Air Pressure Sensor will register the change in vacuum and the ECU will adjust the fuel injection so the fuel mixture will never become an issue, like it would in the bad old days of carbs. In other words, there would be no loss in performance in any but the extreme case of WOT and high RPM.

As for it being somehow harmful to run around with a dirty air filter, that is nonsense. The dirt is on the outside of the filter, not in the engine. The dirtier the filter, the smaller the remaining air passages there are through the filter media, the more completely the filter will filter particles. So while a brand new filter may pass anything smaller than 10 microns, a dirty filter may filter down to 5 or even smaller. That said, you could make the argument that you would be doing your engine a disservice by replacing the filter too soon.

YMMV