K&N filters for flatslides

[coombehouse]

Yes they are supposed to be oiled. Non oiled foam will not trap anything as you say. The ramair oil is quite a thin oil whereas some of the generic filter oil is thick & gooey for Mx. I have had good results with motorex oil which has a lot of solvent & not a lot of oil but it is very sticky & gets everywhere. Best do it in a poly bag. 

Or maybe try a light coat of k&n filter preferably the aerosol type.

[Upshotknothole]

Hell, guess I should oil mine then.

[arnout]

23 hours ago, coombehouse said:

Yes they are supposed to be oiled. Non oiled foam will not trap anything as you say. The ramair oil is quite a thin oil whereas some of the generic filter oil is thick & gooey for Mx. I have had good results with motorex oil which has a lot of solvent & not a lot of oil but it is very sticky & gets everywhere. Best do it in a poly bag. 

Or maybe try a light coat of k&n filter preferably the aerosol type.

Ah.. Using thinner oil makes sense. A fellow Kat owner also experimenting with these RamAirs filters however did use the specific RamAir-oil but experienced similar problems with over rich mixture and sooted plugs.. Perhaps that stuff isn't as thin as the Motorex oil you mention?

I have a spraycan of K&N oil, which is really thin indeed, and I'll probably give that a try first. (Spray on, bag it, work oil through, let dry?)

If that doesn't work (well enough) I might have a go at modifying the dual K&N pods and replace the rubber back flange with a panel of rippled cotton mesh.

[coombehouse]

25 minutes ago, arnout said:

Ah.. Using thinner oil makes sense. A fellow Kat owner also experimenting with these RamAirs filters however did use the specific RamAir-oil but experienced similar problems with over rich mixture and sooted plugs.. Perhaps that stuff isn't as thin as the Motorex oil you mention?

I have a spraycan of K&N oil, which is really thin indeed, and I'll probably give that a try first. (Spray on, bag it, work oil through, let dry?)

If that doesn't work (well enough) I might have a go at modifying the dual K&N pods and replace the rubber back flange with a panel of rippled cotton mesh.

You've got me thinking now. I have a similar problem with a modern bike that has started drinking fuel & the only recent change is I fitted a foam filter. Bugger. Hadn't considered that. 

[arnout]

Slight correction due to misunderstanding:

22 hours ago, arnout said:

Ah.. Using thinner oil makes sense. A fellow Kat owner also experimenting with these RamAirs filters however did use the specific RamAir-oil but his already over rich carb setting also added to the similar problems with over rich mixture and sooted plugs.. Perhaps that stuff isn't as thin as the Motorex oil you mention?

I have a spraycan of K&N oil, which is really thin indeed, and I'll probably give that a try first. (Spray on, bag it, work oil through, let dry?)

If that doesn't work (well enough) I might have a go at modifying the dual K&N pods and replace the rubber back flange with a panel of rippled cotton mesh.

So the thicker the oil you use on foam filters, the more the airflow is restricted but the better the dust/particle retention. So key is finding the happy medium between airflow and protection with the specific type/brand of oil you choose.

The oil I used was quite thick and felt tacky and stringy like glue on the filters. Probably better used for foam filters on off road bikes.

[Gixer1460]

On 8/1/2018 at 11:41 PM, arnout said:

If that doesn't work (well enough) I might have a go at modifying the dual K&N pods and replace the rubber back flange with a panel of rippled cotton mesh.

I'd be very surprised that any K&N would suffer an airflow deficiency! I've used them black with dirt and muck on the outside and inside you could still make out the red oil'd fabric. My turbo had a tiny oval cone filter that wasn't apparently restricting 1460cc on WOT - not saying bigger is not better, but maybe un-necessary?

[Leblowski]

Using the original rubber intakes and ram air filters on my race slabby after setting up on the dyno they have worked flawless, you can’t argue bout price only 25 quid on egay

[arnout]

12 hours ago, Gixer1460 said:

I'd be very surprised that any K&N would suffer an airflow deficiency! I've used them black with dirt and muck on the outside and inside you could still make out the red oil'd fabric. My turbo had a tiny oval cone filter that wasn't apparently restricting 1460cc on WOT - not saying bigger is not better, but maybe un-necessary?

Perhaps I should've explained myself better. Improving the airflow isn't the objective with the modifying idea (especially as the K&N's appear to flow air better than oiled RamAirs already). The idea was to remove the reflective surface -the rubber flange- as to solve the problem with pressure waves bouncing back into the intake. I guess sticking a piece of material that would absorb or deflect these pressure waves onto the inner face of the flange would work too.

7 hours ago, Leblowski said:

Using the original rubber intakes and ram air filters on my race slabby after setting up on the dyno they have worked flawless, you can’t argue bout price only 25 quid on egay

I presume you did not use any oil on the RamAir filters? If you did, what kind (and how much).

For racing bikes air filtration isn't nearly as important as for road bikes as the milage is far less. The aim is just to stop larger particals (plastic bags, birds, nuts/bolts) from getting sucked into the engine and sacrifice as little power as possible.

Yup, these RamAir filters are pretty cheap. And the construction and material seems very good. But if you're not using any oil on foam filters they simply do not filter dust from the air that otherwise gets sucked into the engine. That's when cheap filters become pretty expensive over time.

[coombehouse]

How about replacing the rubber end cap of the k+n with foam. Ramair sell sheets of the stuff & it can be attached with a hot glue gun successfully.

[Leblowski]

10 hours ago, arnout said:

Perhaps I should've explained myself better. Improving the airflow isn't the objective with the modifying idea (especially as the K&N's appear to flow air better than oiled RamAirs already). The idea was to remove the reflective surface -the rubber flange- as to solve the problem with pressure waves bouncing back into the intake. I guess sticking a piece of material that would absorb or deflect these pressure waves onto the inner face of the flange would work too.

I presume you did not use any oil on the RamAir filters? If you did, what kind (and how much).

For racing bikes air filtration isn't nearly as important as for road bikes as the milage is far less. The aim is just to stop larger particals (plastic bags, birds, nuts/bolts) from getting sucked into the engine and sacrifice as little power as possible.

Yup, these RamAir filters are pretty cheap. And the construction and material seems very good. But if you're not using any oil on foam filters they simply do not filter dust from the air that otherwise gets sucked into the engine. That's when cheap filters become pretty expensive over time.

Nope not using any oil must say i doubt that it’s neceserry with these ram air filters they are made from other material then kn filters 

cant find any info on the ram air website either if they need lubrication, i reckon its not neceserry

 

Edited August 4, 2018 by Leblowski

[coombehouse]

http://www.ramair-filters.co.uk/shop/automotive/accessories/foam-air-filter-economy-cleaning-kit-polymer-treatment/

[Gixer1460]

An un-oiled foam filter will just stop rocks etc but sand / dust will pass through as the material is open celled polyurethane - there will be a direct (although convoluted) path from outside to inside.

@Arnout - worrying about intake pulses will potentially be a fruitless / pointless exercise IMO especially for a road bike. Pulse reflections will occur at most changes of area or edges so potentially you have multitude reflections from inlet manifold, throttle butterflies, carb mouth, ram pipe mouth, air filter and probably a few more so a complete jumble. Generally most benefit occurs when engine operates in a constant relatively narrow rev range with minimal intake tract variations / constant taper from intake to valve. Total inlet tract length is widely know to offer best results especially to fill in torque deficiency holes - usually longer picks up torque and can get to daft lengths without loss of top end HP - see http://www.emeraldm3d.com/articles/emr-adj-length-intake/ - its an interesting read.

Edited August 4, 2018 by Gixer1460

[arnout]

11 hours ago, Gixer1460 said:

- see http://www.emeraldm3d.com/articles/emr-adj-length-intake/ - its an interesting read.

Interesting read indeed. Like it said in the article many car manufacturers experimented with variable intake lengths, and Yamaha used a version of this idea on the R1 (separate set of stacks moving in and out).

So the length of velocity stacks/trumpets/ducts/ram pipes/whateveryoucallthem plays a big part in where the engine delivers its torque/power. I think adding a flange right in front of the intakes like is done by fitting dual K&N pods, introduces an extra variable to this equation (that isn't covered in the article).

The article states intake lengths however have no impact during part throttle as pressure waves bounce off the butterfly valves. In case of (flat)slide carbs that would only be the single throttle slide though. Also the issue that's being discussed in this topic is that people DO experience a difference in engine response part throttle between a K&N and a foam filter setup. So I guess where the length of the intakes stops being a factor at part throttle, other variables like the K&N flanges apparently do still play a part in how the engine performs. Perhaps this is more manifest with (flat)slide carbs then CV carbs, as there is less blockage for pressure waves to travel past openings?

It seems this issue is of greater importance for road bikes rather than race bikes as road bikes spend a lot more time running part throttle.

[arnout]

On 8/3/2018 at 11:56 PM, coombehouse said:

How about replacing the rubber end cap of the k+n with foam. Ramair sell sheets of the stuff & it can be attached with a hot glue gun successfully.

I was thinking about getting a cheap used car air filter panel from Eblag and cutting it to size. But using (oiled!) foam filter material would work too of course. Perhaps cut up my set of RamAirs to patch the K&N's 

[coombehouse]

3 minutes ago, arnout said:

I was thinking about getting a cheap used car air filter panel from Eblag and cutting it to size. But using (oiled!) foam filter material would work too of course. Perhaps cut up my set of RamAirs to patch the K&N's 

Ramair sell 300mm square sheets of foam on Eblag. Would seem a shame to cut up the socks you have. Another option is twin air or finna foam. Made in Holland I think.

[Duckndive]

I use a pair of these on my RS38s

Item no 350635171659  on you know where offer them £20

[Upshotknothole]

1 minute ago, Duckndive said:

I use a pair of these on my RS38s

Item no 350635171659  on you know where offer them £20

I'm running those same filters on the same carbs. When I looked up the cleaning/oiling kits from ramair, I found this.

Ramair filters owe much of their dirt retaining properties to the unique advanced polymer treatment with which they are impregnated during manufacture. They can be given a new lease of life when they become heavily soiled by cleaning them thoroughly with Ramair polymer solvent cleaner and applying fresh Treatment to the foam filter material.

So I'm not gonna worry about them until I need to clean them.

[arnout]

21 hours ago, coombehouse said:

Ramair sell 300mm square sheets of foam on Eblag. Would seem a shame to cut up the socks you have. Another option is twin air or finna foam. Made in Holland I think.

Thanks for the tip, but I was (sort of) joking about cutting the foam filters up (for now). 

2 hours ago, Upshotknothole said:

I'm running those same filters on the same carbs. When I looked up the cleaning/oiling kits from ramair, I found this.

Ramair filters owe much of their dirt retaining properties to the unique advanced polymer treatment with which they are impregnated during manufacture. They can be given a new lease of life when they become heavily soiled by cleaning them thoroughly with Ramair polymer solvent cleaner and applying fresh Treatment to the foam filter material.

So I'm not gonna worry about them until I need to clean them.

That's what I found earlier as well but thought was strange and conflicting both with my own experience (new filters feel bone dry, not tacky whatsoever) and the report of others finding dust in their carbs after running the RamAir sock filters for a while.

Perhaps the so called  "polymer treatment" relies on static cling properties to capture dust?? That's the only explanation I can come up with.. 

So.. To get some clarity about it all I tried contacting RamAir with my questions, but have received no response to my repeated queries via the online contact form or via email. Perhaps the email address I had to track down via Google (not on RamAir website) was incorrect? info@ramair-filters.co.uk (Maybe non-UK residents are blocked?)

Maybe someone else can have a go? Of course there is a phone number too, but I'm not a native English speaker. Writing is OK but verbally I'm pretty poor..

[coombehouse]

13 hours ago, arnout said:

Thanks for the tip, but I was (sort of) joking about cutting the foam filters up (for now). 

That's what I found earlier as well but thought was strange and conflicting both with my own experience (new filters feel bone dry, not tacky whatsoever) and the report of others finding dust in their carbs after running the RamAir sock filters for a while.

Perhaps the so called  "polymer treatment" relies on static cling properties to capture dust?? That's the only explanation I can come up with.. 

So.. To get some clarity about it all I tried contacting RamAir with my questions, but have received no response to my repeated queries via the online contact form or via email. Perhaps the email address I had to track down via Google (not on RamAir website) was incorrect? info@ramair-filters.co.uk (Maybe non-UK residents are blocked?)

Maybe someone else can have a go? Of course there is a phone number too, but I'm not a native English speaker. Writing is OK but verbally I'm pretty poor..

I called Ramair today & spoke to a helpful lady. 

Motorcycle filters do not come ready oiled. The stuff they use leaves a sticky residue so you would notice if it was on there apparently.

The sheets of foam they sell are not oiled either.

Interestingly she said you don't have to oil the filter. It depends on how exposed the filter is & the environment it is used in. For an old skool bike with the filters where they are, I guess dry would be fine unless you live by a beach. For modern bikes with front facing intakes, I guess oiling would be essential. 

I have ordered a ramair cleaning kit to see what the oil looks like compared to the motorex oil & the pipercross kit I have.

[Gixer1460]

IMO - if there is no drawbacks to oiling the filter (ie they recommend it subject to use - strange as dust can occur any where anytime?) they why not just oil it anyway?

Obviously they won't as it maybe saves 5p in oil but average Joe - it's not a cost i'd worry about?

[dupersunc]

Oiled filters and wet weather don't go well together,  on the race cars we ran the same foam filters but un oiled in wet conditions. Oiled foam in dry conditions.    You end up with an emulsion forming in the filter in the wet if they were oiled, which was bad for flow.

These were on some of the most sophisticated inlet set-ups ever devised.  

The issue of pressure waves bouncing off the cap on the K&Ns is interesting, and I'm sure a real phenomenon at WOT, of little significance at part throttle openings.  Bell mouths are always the best way to go, as the radius, a full 180 degree rad is best, makes the flow better and create a pressure signal before the Filter.  

I run Slingshot bell mouths in Ram air twin filters, it's the best compromise I feel. an air box and panel filter is a better solution where possible. 

Edited August 6, 2018 by dupersunc

[arnout]

11 hours ago, coombehouse said:

I called Ramair today & spoke to a helpful lady. 

Motorcycle filters do not come ready oiled. The stuff they use leaves a sticky residue so you would notice if it was on there apparently.

The sheets of foam they sell are not oiled either.

Interestingly she said you don't have to oil the filter. It depends on how exposed the filter is & the environment it is used in. For an old skool bike with the filters where they are, I guess dry would be fine unless you live by a beach. For modern bikes with front facing intakes, I guess oiling would be essential. 

I have ordered a ramair cleaning kit to see what the oil looks like compared to the motorex oil & the pipercross kit I have.

Finally some confirmation the filters are NOT pre-oiled! Thank you coombehouse for taking the effort to contact RamAir.

As for the need for oiling depending on the dustiness of the environment is a bit of a vague statement I think. That says to me oiling is indeed required for good air filtration. In a dust free environment there's obviously no need for air filtration (doh!). In the real world I ride my bike fequently past dusty building sites and over dusty country roads.. So I think I'd better oil my foam filters.

10 hours ago, Gixer1460 said:

IMO - if there is no drawbacks to oiling the filter (ie they recommend it subject to use - strange as dust can occur any where anytime?) they why not just oil it anyway?

Obviously they won't as it maybe saves 5p in oil but average Joe - it's not a cost i'd worry about?

The main drawback -as reported- is the decreased airflow of oiled foam filters. The thicker the oil, the more airflow suffers in favor of better air filtration. So a trade-off.

10 hours ago, dupersunc said:

Oiled filters and wet weather don't go well together,  on the race cars we ran the same foam filters but un oiled in wet conditions. Oiled foam in dry conditions.    You end up with an emulsion forming in the filter in the wet if they were oiled, which was bad for flow.

These were on some of the most sophisticated inlet set-ups ever devised.  

The issue of pressure waves bouncing off the cap on the K&Ns is interesting, and I'm sure a real phenomenon at WOT, of little significance at part throttle openings.  Bell mouths are always the best way to go, as the radius, a full 180 degree rad is best, makes the flow better and create a pressure signal before the Filter.  

I run Slingshot bell mouths in Ram air twin filters, it's the best compromise I feel. an air box and panel filter is a better solution where possible. 

Filter oil and water turning into an emulsion sounds bad, but perhaps this is more likely with "bio" filter oils than conventional petroleum based filter oils?

Bell mouths is a variable not yet well addressed in comparing K&N cotton-mesh and RamAir foam filters. Perhaps the absence of bell-mouths/stacks with running K&N filters contributes to the poor part throttle response behavior now attributed to the closed end cap ?

It seems to me the optimal "pod filter" would be a combination of parts of both types. A cotton/mesh material covering the whole pod and a incorporated velocity stack to mount the filter as one unit onto a carb.

[dupersunc]

7 hours ago, arnout said:

 

The main drawback -as reported- is the decreased airflow of oiled foam filters. The thicker the oil, the more airflow suffers in favor of better air filtration. So a trade-off.

Filter oil and water turning into an emulsion sounds bad, but perhaps this is more likely with "bio" filter oils than conventional petroleum based filter oils?

Bell mouths is a variable not yet well addressed in comparing K&N cotton-mesh and RamAir foam filters. Perhaps the absence of bell-mouths/stacks with running K&N filters contributes to the poor part throttle response behavior now attributed to the closed end cap ?

It seems to me the optimal "pod filter" would be a combination of parts of both types. A cotton/mesh material covering the whole pod and a incorporated velocity stack to mount the filter as one unit onto a carb.

There is no decrease in flow if filters are oiled.  That's incorrect.

Some of the large Cone type K&N filter have a bell mouth moulded in.  

[coombehouse]

Ramair regeneration kit (their words) arrived today. Expensive for what you get. The cleaner is some sort of detergent. They say it can be reused. The oil is very thin & not sticky like normal filter oil. Doesn't smell strongly of solvent but does dry quickly on the hands to leave an oily residue, not tacky but you know it's there. 

When it's in the bottle it has the viscosity of fresh milk. No thicker.

The instructions say for general road use, filters only need a very light coating of oil, over oiling can cause restriction to the filters use.

The pipercross oil kit I have looks to be better as it's 2 X aerosols though again only small 100ml, but make application easier. Just dust on a light coat & let it soak in. The oil viscosity & tackyness seem about the same. See pics for what you get from Ramair.

[arnout]

9 hours ago, coombehouse said:

Ramair regeneration kit (their words) arrived today...

Cool.. Thanks for the write-up. I have oiled my set of RamAirs with K&N oil but haven't been out on the bike yet to try them out (due to blistering heat and oddly enough me having a cold at the same time.)

14 hours ago, dupersunc said:

There is no decrease in flow if filters are oiled.  That's incorrect.

Some of the large Cone type K&N filter have a bell mouth moulded in.  

Uhmm.. The whole point of me digging up this topic is that I found the spark plugs on my Kat had turned black with soot after switching from dusty old K&N-pods to OILED RamAir filters. Plenty of other sources also confirm oiling foam filters (to make them actually work) decreases their airflow, BUT I've now learned it probably makes a big difference to as what type/thickness of oil is used in relation to how much airflow suffers. I've also now understood I used the wrong type of foam air filter oil and probably over-oiled the filters too.

As you're a car racer you might find this discussion interesting: click.

Found this email correspondence with RamAir via Google:

Quote

Good Morning Stephen,

Our filters are supplied in dry form (pre-impregnated), however to increase the air filters dirt loading efficiency you can add our oil to it. This does reduce air flow slightly but in dirty/dusty climates the extra help is needed.

With European road use certainly with panel filters they do not require oiling, the maintenance like you said is simply washing them in soapy water, rinse and then allowing them to dry.

Best Regards

Ryan Davies
Sales
Ramair Filters Ltd