What would cause this?

[Foxhound013]

So at the last race a bunch of silt made its way to my pre filter (we took a mower filter and put it in our lid) and caused my bike to not run worth a crap. Needless to say I didn't figure it out until after I DNFed. So we took a K&N, (well a spin off, but simmiliar to the k&n) and put it in our lids, it now covers the entire lid for the most part but when we start up the bikes they blow black smoke when we rev it up. Black smoke means rich dosn't it? I didn't think it made any sense because technically it should flow better now and be on the lean side not rich. Whats going on?

[d3ktrix]

Does it still smoke with the lid off?

Does it only smoke black when the bike is cold? or also once warmed up?

And yes ur right, black smoke means rich.

[Foxhound013]

I haven't tried much on it yet, I'll give it a shot with the lid all the way off to see what that does.
Dosn't make any sense that it would restrict more air than a paper filter.

[Mike Pittman]

My brother uses a outerwear prefilter on his Yamaha yzf450. It works great. We let laz owner of GT thunder and hauns owner of HMF see it back in 04 and now one of them make and sell it

[Mike Pittman]

Also read up on paper filters they are not meant to be used in dusty or wet and muddy riding. After a paper filter gets wet and dirty they clog restricting the air flow. That's why you never see a top pro gncc rider, with pro builders using a k&n

[2001400exrida]

Originally posted by Mike Pittman
Also read up on paper filters they are not meant to be used in dusty or wet and muddy riding. After a paper filter gets wet and dirty they clog restricting the air flow. That's why you never see a top pro gncc rider, with pro builders using a k&n

K&N filters are not paper, they are cloth.

A k&N with a pre filter on it such as an outerwears lid or an outerwears sleeve hold out plenty of crud. I run both K&N and uni and there are several GNCC guys that run k&n's with pre filters. the foam filters get covered in debris too.

Dune guys prefer k&n because the UNI"s get clogged so bad with sand.

Yes, i use the Uni when the conditions are muddy and wet and dirty, but i run the k&n through the same conditions and with that pre filter my k&n stays clean. I don't run an airbox lid so both filters are seeing lots of dirt and mud when i ride hare scrambles.

I have yet to see dirt or grime in my intake with either filter and as i mentioned they both see lots of dirt.

[Mike Pittman]

Yes you probably don't see the dirt and debris on your intake. But dino your bike aftera the k&n has been wet or dirty. Watch how much faster you burn up your rings
And you should see dirt on the outside of any filter not sure about your point on that but everybody can make the right choices on air filters so keep running paper filters in the dust and mud and I will be waiting for you at the finish line holding another trophy
Furthermore why would you be continuously switching air filters in the middle of the season your bike has got to be horribly miss jetted. Jet your properly and you will notice a huge difference

[2001400exrida]

For the record, switching from a k&n with a pre filter to a uni filter does not make my bike run any more lean or rich. I switch because i like to always keep a clean filter and depending on sand or mud or what, i prefer to run the proper filter.

I've been running k&n's on my machine with the pre filter for 4 years now and it's still on stock motor, so i'll be right there next to you at the finish :)

My quad does not require a rejet for the k&n filter, i think the outerwears pre filter on it restricts a little airflow thus keeping it pretty close to the uni. The pre filter gets dirty but the k&n is always clean after my rides, sometimes i can just clean off the prefilter and skip the filter cleaning for every other ride.

Also, my bike is jetted just fine, thank you

They are not paper! get that through your head bud.

[Mike Pittman]

Im sorry for calling it paper filters, you are correct it is not paper it is cotton and gauze.

If I get a boo boo and run out of gauze i reach for a PAPER towl

Im playing on that