K&N Air filter

[bladeowner]

If anyone's in the market ....Just bought a K&N air filter - SU-1002 from Amazon for just £29.26 less than half the price of Sportsbike shop. Only a couple left.

[Ianmc]

     Why not just buy the standard filter for around£15-17 delivered to you door.Then wash your original out and keep it until the next change is required.
       

[mr_diver]

Washing paper filters makes them clog up more as they breakdown with water.

K&N filters can be washed and oiled. Mine has done 30k miles and cost £38. So I'm spending less on one K&N than three papper ones.

[bladeowner]

I've had one in my Fireblade for the last 17 years. Still looks like new. In the unlikely event I sold the 'blade I could put the original back in and sell the K&N for more than I paid for it I bet.

[Ianmc]

     In a previous life (in the 70’s) I worked for a company that had about 20 trucks, we used to service the engines and change air filters then wash the old filter with non- biological washing powder.Never had a problem.Its the manufacturers that spread rumours about them breaking down so you will buy new.I have had a spare since 2015 and changed it / washed it several times with no problem whatsoever and it still looks like new.In fact it is in my L2 now.It’s an acknowledged fact in the trade that K&N air filters let minute particles into the engine whereas the standard filters block them.Just my two pence worth.

[bladeowner]

You are maybe right about small particles but actually in the real world it maybe doesn't matter. This bloke tested his K&N filters over 2 years  in 2017
and then again in 2019

[Rixington43]

Biggest issue with lifetime filters is the people who think that 'lifetime' translates to 'maintenance free' and so never wash them or re-oil them, I can completely believe they let more minute particles through if they're dry as a bone as my understanding is the oil does a lot of the dust catching.
If they're left to get as bad as mine was when I bought the bike then they let naff all through as they are essentially a solid matt of dead insects and fluff 

[bladeowner]

I agree.  According to K&N the minute particles have a better tendency to catch on the oil and micro fibres as opposed to going through the holes in a paper filter but I guess they would say that. Anyway my Fireblade has done 70000+ miles without any issues engine wise using one and so I think the Strom will be OK.

[Mr Nick]

Never felt the desire to wash out a single use paper filter, in the same way I don't wash out loo roll or tissues. Also never been a fan of cotton filters as there's better alternatives out there for greater flow without compromising filtration, like multi-layer foam.

[Rixington43]

I do prefer Pipercross filters if I'm buying it myself but I'm too tight to replace a free K&N 🤣.

[Gert]

Not sure whether anyone may be interested in this DIY air filter as an alternative, http://s207653679.onlinehome.us/wsb4547739201/Air%20Filter.htm ? Haven't tried it myself but it was interesting to read what can be done, if in a pinch.

[kwackboy]

Nothing wrong with K&N filters, I've had them in many bikes over the years, the most was an old CB500 and, when I owned it I covered 50k miles. That poor bike was thrashed to an inch of it's life on many trackdays, it's still going with over 120k on the clock .
I even had one in my Audi for 30k miles.   

[Mr Nick]

I think your filter choice needs to follow the environment you use the bike in: I wouldn't be using a cotton filter in dusty conditions, but around town or on track they're OK.

As far as rebuilding a filter goes, you can get one for £15 for a Strom so why would you consider going to that trouble?

[macvisual]

Within the past two weeks I removed the K&N air filter from my DL1000 and used a K&N service kit, washed and re-oiled, then road tested and what an improvement. I highly recommend K&N...!

I also removed the rubber Snorkel from front of air-box to help induce more air intake into box, there's a lovely induction sound under acceleration.

mac

[Rixington43]

Hello Mac

Yes the difference after a good wash and re-oil is pronounced. You may find the increased induction noise is as much to do with that as anything else.
I'd be cautious removing the snorkel though.
If yours is a first gen Vee then air is drawn in between the top of the radiator and the bottom of the headstock (there's even a nice metal plate there to channel the air between the plethora of cables and into the space behind the headstock).
That snorkel is presumably there to direct the updraft behind the headstock into the air box, removing it might actually reduce intake pressure even if the noise is more audible.

[Mr Nick]

If the airbox was more efficient without the snorkel then Suzuki wouldn't have gone to the trouble of designing it and the expense of fitting it. As well as catching air from an area that is better in terms of flow, maybe there's a temperature difference as well. Warm turbulent air will do wonders for intake efficiency.
But we all know that more noise has to equal more power though...

[Rixington43]

Please excuse the Fischer Price CFD here Mac, I'm not trying to be patronising by drawing pictures but I thought it might help explain the specifics for the V-Strom.
The gap between the radiator and headstock has a clear line of sight to open air when the bike is in motion and so there will be a nice, high speed, laminar flow being created by that smooth metal plate and then forced upwards when it hits the front of the airbox. The metal plate is even angled slightly upwards to assist this.
With the snorkel fitted, all this air is marshalled into the airbox and the smooth bend in the snorkel will mean nice clean airflow going into the airbox.
Remove the snorkel and most of that airflow will go straight past the inlet and either exit behind the handlebars or swirl around under your tank.
It will certainly make a lovely wooshing but I really would consider refitting it if optimum airflow is your goal. The cleaned filter alone will do plenty for the induction noise.

[TLPower]

Excellent drawing skills there Rixington, they deserve a special place in the gallery.