[NMKawierider]

                                                                                     Air Filter Overkill?  Maybe.

Ever sense I installed the new Twinair filter I had some worries that the reduction in surface area over the pleated paper OE filter was going to have an effect on air quality and flow but no one reported any issues and it seemed that the conversion to these Unifilter and Twinair 5” and 6” filters were just fine so I quit thinking about it. Then I was noticing that my outer mushroom filter was doing a great job, but was having to be cleaned after almost every dusty ride otherwise it became restrictive. I wanted to go longer as I take trips that may last for a week or more and didn’t want to fool with it so I wanted the biggest two stage Unifilter I could get in there..and a water resistant Outerwears prefilter so I bought this 3x5x8” Unifilter:

https://www.amazon.com/gp/product/B00A3HLF4A/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Although the filter area was 8”s long with the end caps it was closer to 10” so to install it where I wanted to required an..”adjustment” to its internal cage. So I did it and installed it and it looked like this:



A little scrunched in there and didn’t like it. So, in the meantime I found that my Intake pressure & temp sensor  was coated with filter oil which told me at times…probably at WOT the.. air is being pulled through the TwinAir hard enough to pull some filter oil out and into the intake. And I’m not one to over-oil a filter nor install and run it before it dries. So to me it was clear I needed a filter with more surface area, and I had about 8.5” of room in the box. It could be a maximum of 5”s in diameter. I tried the new Uni in there and with the adjustment I made it would go but would have a little deflection. I decided to do it but needed to adapt the 3” inlet down to the 2.25” of the OE adaptor. Couldn’t find exactly what I was looking for but did find this 9-dollar cone filter with adaptors to go from it’s 4” base to 2.25” so..I bought it for the adaptors mostly. This one:

https://www.amazon.com/gp/product/B00MC64AZ6/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I was able to use them on the UniFilter to get me down to the 2.25”



And still not increase the length at all:



I did have to cut the OE adaptor’s lip on the filter side off so the center ridge would set flush and rest properly in the filter adaptor. Then with some finesse and the clamp off, I was able to install it in the airbox:





And for fun I installed the blue gauze filter on the external port as I still had adaptor parts to go from the 3” up to it’s 4”. It’s intended to be a dry-type filter but can be oiled with K&N oil and is large enough for a V-8 so I might try it for a bit.



Now if I just had an Outerwears prefilter for it….this is getting expensive!
 

Just a side note: Check your Air Temp & pressure sensors if you have been running a Uni or TwinAir. If it gets an oil coating it will send a false reading to the ECU and it will run extra lean. Mine now runs richer enough that I can tell in the exhaust. Only use the spray Mass Air Sensor cleaner on them..nothing else or you will damage it.

[bezerk1]

I do not believe that the ZForce uses a mass air flow sensor.  The fuel injection on these engines use the speed density algorithm.  It would require a manifold pressure sensor and a air temperature sensor.  I'm not sure that any off road motorcycle, atv, or sxs use the mass airflow system due to concerns of contamination and vibration.

[NMKawierider]

I do not believe that the ZForce uses a mass air flow sensor.  The fuel injection on these engines use the speed density algorithm.  It would require a manifold pressure sensor and a air temperature sensor.  I'm not sure that any off road motorcycle, atv, or sxs use the mass airflow system due to concerns of contamination and vibration.

The parts list does call it a Air Temp and pressure sensor so I changed it. Thanks. Mine was covered with oil and had some residue on the butterfly. The only place it can get that was incoming air so it has to be the foam filter oil. I was also having some issues with my truck with a K&N and when I pulled the mass sensor out of it, it was also covered with oil...red K&N oil. Now it runs good again.  Anyway...it would appear being covered with oil isn't a good thing....for either.

Beginning to wonder about these oiled air filters in EFI machines. For sure I will be rolling them up in a dry paper towel...inside and out when re-oiling to get any extra out. I like and trust their abilities enough to keep using them.

[BoatFixx]

I've used a K&N on my Cummins for over 200k miles now.
I wonder how they would do in these machines?
I just took delivery of a 21' 800 Trail

[NMKawierider]

I've used a K&N on my Cummins for over 200k miles now.
I wonder how they would do in these machines?
I just took delivery of a 21' 800 Trail

Not well. Too much dust volume for K&N. When clean they let too much fine through (40 micron and smaller) then when they get packed-up enough to filter well, the pulses from the intakes flexes the wire frame and in time..(only one ride for this guy), the wire fatigued and long cracks opened up letting it all in destroying his top end. Other types to the same even the TwinAir foam filters. Only a properly serviced Unifilter has proved to worthy of trust.



 

[glenlivet]

I've used a K&N on my Cummins for over 200k miles now.
I wonder how they would do in these machines?
I just took delivery of a 21' 800 Trail

Congratulations on the Trail, I have one myself.
Seriously though, for severe duty and an ATV/SXS a K&N filter is a very poor option. Numerous independent tests can be easily found that bear this out.
The problem seems to be that K&N were designed for show cars, their gauze and burgundy color thin oil complementing chromed engines. Trouble is, people started using them for actual air filters and K&N were stuck, married to the original but poorly performing design. So they doubled down, selling a 'prefilter' which now filtered somewhat better but increased the resistance to air flow. Basically they added an air filter to the air filter so that it might actually filter air, at a cost to performance.
Your SXS is going to be operating in much dustier conditions than your truck and I'd say it would be way more prudent to get a good oiled-foam filter.

BTW, don't use up any of your left over purple K&N oil on a good foam filter, K&N oil is just thin oil with no special properties and in a foam filter it will seep down to the low part of the filter leaving the upper part dry. Proper foam filter oil is very tacky oil suspended in a thin and volatile oil carrier. When properly applied this oil is distributed evenly through the foam and in the next hour the volatile component evaporates leaving a thin and tacky residue all through the filter. K&N oil is pretty much colorful dyed sewing machine oil. 
It's a big and recognized name, that's all. I would avoid it.

PS: pop that grill off between the seats (4-8mm push pins) and have a look. The intake point is a 2" circle on the back side of that gray plastic plenum. the intake with its prefilter sock is wide open to the ground, the back tires, kicking up dust, and also open to the hot engine. There should have been an airtight connection from the air box plenum to the intake grill between the seats, but there isn't one.

It's a good idea to clean the air cleaner element often (some guys say they do it every ride!), and please consider snorkeling the intake or boxing off the intake behind that grill so that your motor stops inhaling your own back tire dust.

Sorry to sound obnoxious if I do, Just sharing what I have learned. I'm in my 4th year of ownership and have had almost zero issues with my 800 CFMoto. You have a good machine there. 

[BoatFixx]

I've used a K&N on my Cummins for over 200k miles now.
I wonder how they would do in these machines?
I just took delivery of a 21' 800 Trail

Congratulations on the Trail, I have one myself.
Seriously though, for severe duty and an ATV/SXS a K&N filter is a very poor option. Numerous independent tests can be easily found that bear this out.
The problem seems to be that K&N were designed for show cars, their gauze and burgundy color thin oil complementing chromed engines. Trouble is, people started using them for actual air filters and K&N were stuck, married to the original but poorly performing design. So they doubled down, selling a 'prefilter' which now filtered somewhat better but increased the resistance to air flow. Basically they added an air filter to the air filter so that it might actually filter air, at a cost to performance.
Your SXS is going to be operating in much dustier conditions than your truck and I'd say it would be way more prudent to get a good oiled-foam filter.

BTW, don't use up any of your left over purple K&N oil on a good foam filter, K&N oil is just thin oil with no special properties and in a foam filter it will seep down to the low part of the filter leaving the upper part dry. Proper foam filter oil is very tacky oil suspended in a thin and volatile oil carrier. When properly applied this oil is distributed evenly through the foam and in the next hour the volatile component evaporates leaving a thin and tacky residue all through the filter. K&N oil is pretty much colorful dyed sewing machine oil. 
It's a big and recognized name, that's all. I would avoid it.

PS: pop that grill off between the seats (4-8mm push pins) and have a look. The intake point is a 2" circle on the back side of that gray plastic plenum. the intake with its prefilter sock is wide open to the ground, the back tires, kicking up dust, and also open to the hot engine. There should have been an airtight connection from the air box plenum to the intake grill between the seats, but there isn't one.

It's a good idea to clean the air cleaner element often (some guys say they do it every ride!), and please consider snorkeling the intake or boxing off the intake behind that grill so that your motor stops inhaling your own back tire dust.

Sorry to sound obnoxious if I do, Just sharing what I have learned. I'm in my 4th year of ownership and have had almost zero issues with my 800 CFMoto. You have a good machine there. 

Hey not obnoxious at all, just very good info!
We use K&N on engines we've installed in yachts but as you can imagine, not too dusty in there
And, my truck? Well, after reading some current tech articles I'm taking it off and going back stock!
I looked at my 800 trail air intake, and what an embarrassment it is! Seriously??? Did they really do that?
It is useless without blocking it off so it only intakes from the cab!
I think for our intended use, simply pulling from the cab should be fine.
If I find that not ample, I'll run up a snorkel.
Funny thing is on my 2021' (may be the same on older models) the CVT air intake is devoted to the cab behind the driver's seat.