Put a K&N air filter into my ZForce 800. After 200 miles I started smelling burning oil in the cab and my performance started to drop.

Got it home, and found Oil splattered all around the p/s rear wheel. After some searching I found the air-box drain pipe was dripping oil. Cracked open the airbox and found it was full of oil. The crank case vent tube was filling the airbox with blow-by. Then I looked at the air filter and this is what i found...




There were no signs of an animal getting into the box. The pre-filter on the intake was still intact and their were no pieces of the fibers in the box.

Ended up getting sand sucked right into the motor. 550 miles on my machine i got 6 weeks ago and the motor is trashed. K&N is washing their hands of it because they dont warranty their off road products. Not to mention their junk filters arent even made in the US anymore.

[2015 Z Force 800 53/Trail EPS]

Oh man..so sorry to see that. I quit using K&N on my off-road toys many years ago because of other reasons...that also damaged one of my engines. I read a report somewhere that said in some cases when one gets enough restriction they start to suck-in and pulse with the intake and on a line that collapse that in time breaks the screen material and open up an actual crack in the filter media. Never actually saw an example...until now. F'n K&N...

I was trying to figure out how that happened. NMKAWIRIDER might be on to something. The filter does look pretty clogged.  I don't have the filter in my hands so can't say for sure. It is going to be a lot of work to do the repairs and emersonsc, I feel for you. Is there any particular trait we all should be looking for in an airfilter?

[2015 Z Force 800 53/Trail EPS]

All I know is that foam filters with the correct treatment/oil is always the best. After I use up my last OEM filter I have in stock, I'll be switching to a Unifilter or TwinAir.

All I know is that foam filters with the correct treatment/oil is always the best. After I use up my last OEM filter I have in stock, I'll be switching to a Unifilter or TwinAir.

I agree. I will be looking for a Unifilter or TwinAir replacement (if anyone knows please let me know!)

The filter does look more clogged than it was. I live in an area with very sandy trails so we have to clean our filters often here. It does seem to coincide with what was mentioned above that the pulsing weakened the screen. The area where the tears are is very brittle so its either that or poor craftsmanship/materials. The filter (i found out after this happened) is manufactured in Mexico... so yeah, so much for quality.

[2015 Z Force 800 53/Trail EPS]

I think Jason has a post on a Uni somewhere here

Wow, that is terrible.  Is the dealer going to help you at all?  Hopefully they will do something for you. 

All I know is that foam filters with the correct treatment/oil is always the best. After I use up my last OEM filter I have in stock, I'll be switching to a Unifilter or TwinAir.

Do happen to have a part number fot the Twin Air filter....thats what I had on both my Can Am's. They always seemed to work well!

[2015 Z Force 800 53/Trail EPS]

All I know is that foam filters with the correct treatment/oil is always the best. After I use up my last OEM filter I have in stock, I'll be switching to a Unifilter or TwinAir.

Do happen to have a part number fot the Twin Air filter....thats what I had on both my Can Am's. They always seemed to work well!

Bezerl1 posted this. He and Jason have it. Unifilter is as good as TwinAir. I have had both:

http://cfmoto-forum.com/800ex800/uni-air-filter-part-number/

and here it is on Amazon:

http://www.amazon.com/Uni-Air-Filter-Two-Stage-Pod/dp/B001IZKIZ8

Hey guys I've been busy all day and just now checking posts, but I'm liking my filter. It fits great just make sure you get the plastic neck that the filter mates with installed the right direction.  I happened to learn the hard way lol.

What happened to that K&N that caused it to rip like that? 

[2015 Z Force 800 53/Trail EPS]

What happened to that K&N that caused it to rip like that? 

The vacuum pulse of the two cylinders intaking causes the filter to actually suck in and back out as it pulses. As the filter gets more restrictive..ie dirtier, this action on the media structure become more pronounced in weaker areas and the more it does it, the weaker those areas become until like wiggling wire back and forth, it fatigues and breaks. Take a small plastic bottle like a milk jug and pull the air out and back in. You will see it crease in the same areas every time. Keep it up and in time those spots will crack first.

You would think that a failure from vacuum pulsing would occur along the pleats and not across them in the center of filter at the weakest point.  It would pull the filter media in and not rupture the screen.  Those pictures look like there was abrasion or crush damage to the filter.  That being said, oiled foam is the way to go.  I've used Twin Air and Uni filters for decades without any issue.  A K&N does not belong in an off road enviroment.

You would think that a failure from vacuum pulsing would occur along the pleats and not across them in the center of filter at the weakest point.  It would pull the filter media in and not rupture the screen.  Those pictures look like there was abrasion or crush damage to the filter.  That being said, oiled foam is the way to go.  I've used Twin Air and Uni filters for decades without any issue.  A K&N does not belong in an off road enviroment.

The filter was brand new out of the box when it was installed. No signs of damage at the time. I have read some where else that K&N filters are prone to this especially after they moved production to countries with a shyte track record of quality.

I have a uni on order that should be here today. I put in my parts order with CFMOTO yesterday, so hopefully I can get my rig up and going here soon. Just hoping I can figure out some alternative to the crap intake tube set up.

Well after a couple parts orders trying to get everything we needed to rebuild the top end, getting the rig put together, going through the break in process, I finally was able to go out and hit the trails...

or so I thought.

Got barely a mile down the road and the rear cylinder connecting rod let go. NOT happy.

I was assured their bearings could withstand what it went through, even after we explained and showed just how bad the airbox failed and how much sand the engine had ingested.

In fact, our good friends unit had to be trailered back to the shop last night because they were having a hard time getting it to start and when it did it ran like crap. Come to find out their airbox had failed too and it took out the rear cylinder (the rings literally fell off as we took the cylinder off) and the crank was shot. He only had 712 miles on it.

We are not at all impressed with the CFMoto units and their poor quality/reliability.