K and N air filter?

I am wondering about one of the re-usable K and N air filters for my Norge. Any views/experience? Do they make any noticeable difference to the power or fuel consumption, or smoothness? Worth doing?

Looks like they are about 5 times the price of a disposable, but supposed to last the life of the bike. How do you clean them, and how often?

Sorry, loads of questions, not experienced in these matters.



I’ve got K&N in both my bikes. Looking forward to not changing them, just cleaning. They don’t block up like paper filters, I would recommend. I bought a cleaning kit with my first filter and it’s still got plenty left. I’ve cleaned the MG filter 3 times now. See this link ref cleaning.

Like Steve I have been using a K&N replacement on my 2004 Triumph for about six years. It’s hard to reach so I only clean and oil it with the K&N kit every couple of years. It wasn’t a lot more expensive than an OEM filter so I’ve made a saving in the process.

Actually K and N’s can block up quite quickly, and the commonest mistake is to over oil them. Which is very easy to do. Ideally need the special K and N cleaner fluid and oil. Mine didn’t last as long as i had the last bike I used them on. The cotton filter material basically disappeared, leaving just the wire gauze, I.e. a load of big holes. They were quite old though. Bear in mind these filters were originally developed for competition, so don’t need to work as long as for a road bike, and from I’ve read, don’t. My opinion has changed, I probably wouldn’t use them again, but stick to stock paper filter which will have a longer service life.

My K&N is a foam rubber direct replacement for the Triumph one, fitted into the OEM air box, not the bolt on cone cafe racer type.

If that’s what the OP meant, fair enough. Must confess I have no experience of that type.

My K&N fits in the original air box. IMHO it’s the best way, rather than the cone type.

Thanks all. The one I was thinking of was the one that replaces the standard one in the air box. It is cylindrical with pleated filter media. See


Still wondering if it makes any difference to the power delivery etc.

I doubt it. I think the advantage will be that the power does not drop off over time.

From what I can gather on grisoghetto the paper filter is best and generally not to use K&N, It depends on how easy it is to get to and if you really want to extract every ounce of power.

Fuel economy would be the indicator if you do change unless you have access to a dyno.

Generally the paper filters I am taking out are in a fairly clean condition.

Well I can report that the K and N has made no noticeable difference either to the power delivery or the fuel consumption. The paper filter I took out was fairly clean.

So the main advantage seems to be the long life. I did find it somewhat easier to fit than expected though. Taking the fuel tank off proved rather simpler than I thought, although I did not manage to disconnect the fuel line. I could rest it upright while working on the filter though.

I am assuming I can just inspect it every 12000 now and clean if necessary.

An interesting series of tests, comparing different brands of air filters. I saw this posted somewhere a while ago, but lost it. Pretty sure this was the one tho.


I have used K&N on two big blocks, they were the larger oval size that sit over the top of the gearbox and in front of the battery, not the small ‘pod’ shape ones. (I tried a couple of those on the LM, cos it had not filters at all, but hey didn’t last long and came off again.)

The large oval K&N’s I put on the 850 (I also had them on the previous Spada) did not last forever. After about 5 years or so, I finally noticed that the cotton filling had largely disappeared, leaving mostly just the wire mesh, i.e. with big holes that will let grit sized particles through. So needed to buy a new pair. Cleaning and oiling them is not simple either and you need the proper stuff for it. Too much oil and they are effectively clogged, so need doing again.