(10-27-2021, 09:44 AM)Whoops_imp Wrote:

(10-27-2021, 06:46 AM)The ferret_imp Wrote: I replace my plugs and air filter every 25,000 miles, even though it is still running good at that point. It's just an easy number for me to remember, 25K, 50K and the next one coming up 75K

By my math that’s about 3 weeks.

(10-27-2021, 09:50 AM)Dave_imp Wrote:

(10-27-2021, 06:43 AM)j3gq_imp Wrote: Unlike oil filters, an airfilter can easily be checked visually, and kept until it gets dirty. cleaning is often easy too. But you won’t save much, as they’re not expensive.

Actually, they are expensive, more than any air filter I have ever purchased in my life, including motorcycles and cars. I just checked an on-line price, and it is $49.68 plus tax, plus shipping.

(10-27-2021, 07:28 AM)max_imp Wrote: We all have our reasons to replace filters and it is good to hear some useful numbers and results.
Sometimes i cannot help myself and look for ways to quantify or measure the size of the problem, I'm curious.

So i looked at some pictures and one showed the drain tube at the bottom of the air filter, this is a clear tube which ends in a black plastic removable plug at the end and is easy to access, since it is in the space of the airbox which is after the filter i thought i could measure the small difference in air pressure when the engine is running.
The result is this small video which shows the change in pressure ( the differential ) across the air filter which has had 57.000 easy kilometers of use.

Could be someone can repeat this test and tell their values, mine only recorded 4 mm. of rise in one end of the tube, the other of course went down by the same amount, hope this sheds some light on the capacity of the air filter;

https://youtu.be/BUrSE-w4zfg

Also wondered if the breather pipe of the positive crank case made a difference, removed the oil filler cap to check and found zero difference in the measurement, i guess my blow-by is not significant enough at this stage.
With my riding style I'm with Tev, it's a big area, so see for yourself.

(10-27-2021, 09:50 AM)Dave_imp Wrote:

(10-27-2021, 06:43 AM)j3gq_imp Wrote: Unlike oil filters, an airfilter can easily be checked visually, and kept until it gets dirty. cleaning is often easy too. But you won’t save much, as they’re not expensive.

Actually, they are expensive, more than any air filter I have ever purchased in my life, including motorcycles and cars. I just checked an on-line price, and it is $49.68 plus tax, plus shipping.