Uni NU-4046 In Stock Airbox -- Any Jet Changes Needed?

[SenseAmidMadness]

Hey folks, got a question regarding a stock replacement oiled foam filter: the UNI NU-4046. Couldn't find any threads on it in this forum.

This is for a buddy's 1980 CB750F, which has already been rendered not-original by multiple previous owners. It currently has a set of horrible cheap pod filters and, of course, won't run right or idle at all. I'm putting a stock airbox back on it and rebuilding the carbs, and the plan is to make it more of a scrambler so he can explore both paved and unpaved roads.

For that kind of riding I think he'd be better served by an oiled foam filter over the stock paper, and UNI is the only option I know of. Their literature says the filter flows more air than stock. I can't find any recommendations for whether it needs to be re-jetted or not, however. I'm also wondering if I could compensate for the slightly higher air flow by getting some of UNI's bulk foam and cutting a small pre-filter to fit inside the rubber snorkel on the back of the airbox. That would also help with keeping dirt out of the inside of the airbox and off the main filter.

Anybody know if I'd need to go up a jet on either the pilots or mains?

 

[BAHNST]

Generally drop in (with airbox) oiled foams and even K&N dont need rejetting on most bikes/older Hondas...
You may find that mixture screws will need adjustment from where they currently set...
Others will report no adjustments at all needed....
Be careful not to over-oil the UNI!

 

[Davidson750]

The only problem with the "UNI" is that you will still need your cage for it.. I recommend HI-FLO-FILTRO HFA1706.. it will give you all the performance that bike needs without jetting or oil.

 

[SenseAmidMadness]

The only problem with the "UNI" is that you will still need your cage for it.. I recommend HI-FLO-FILTRO HFA1706.. it will give you all the performance that bike needs without jetting or oil.

I'm asking about the UNI because he plans on riding his bike in dusty, and possibly wet, offroad conditions. As far as I know, oiled foam filters are better for that.
What do you mean by "still need your cage"?

 

[Biebs]

I'm asking about the UNI because he plans on riding his bike in dusty, and possibly wet, offroad conditions. As far as I know, oiled foam filters are better for that.
What do you mean by "still need your cage"?

Stock style air filters are more than adequate for all riding conditions.

As far as I know K&N oiled filter are garbage!! Millions of dollars spent on marketing but still garbage!!
Uni filters fall in the same category just piggy backed off of K&N marketing.

As far as I know…..

 

[Davidson750]

I'm asking about the UNI because he plans on riding his bike in dusty, and possibly wet, offroad conditions. As far as I know, oiled foam filters are better for that.
What do you mean by "still need your cage"?

If you look at the uni air filter it has no structure, or frame it is just foam.. on a motocross bike we call it a cage or a frame and the filter would go around it, you really only need an oiled filter in severely dry and Dusty conditions hence Motocross or trail riding

 

[BAHNST]

FWIW....If riding in dusty conditions you might want to use a airbox fliter gease around the stock/hiflo filter sealing ring..if not doing already...

 

[Old_Crow]

If you look at the uni air filter it has no structure, or frame it is just foam.. on a motocross bike we call it a cage or a frame and the filter would go around it, you really only need an oiled filter in severely dry and Dusty conditions hence Motocross or trail riding

I had a pair of those Uni filters on an old Triumph Bonneville chopper I built. My dog apparently thought they were delicious, as he ate both of them.

 

[SenseAmidMadness]

Stock style air filters are more than adequate for all riding conditions.

As far as I know K&N oiled filter are garbage!! Millions of dollars spent on marketing but still garbage!!
Uni filters fall in the same category just piggy backed off of K&N marketing.

As far as I know…..

K&N are definitely garbage for street use and there's plenty of independent testing to back it up.

UNI filters are actually used on loads of race-winning dirtbikes, and pretty much every dirtbike and ATV ever made comes with a stock foam filter of similar design. They're in plenty of dual-sport motorcycles too, like a Honda CRF230L I worked on recently. Heck, even a couple of Yamaha Zuma 50's I've worked on came with dual-density oiled foam filters and those are street-oriented scooters.

I figure for a whole $30 it can't hurt too much to experiment with a UNI filter for a few thousand miles -- and I think I'm also going to fabricate an oiled foam "pre-filter" of sorts to fit into or over the snorkel at the back of the airbox to catch the worst of the dirt. This will mimic an arrangement that's commonly used on BMW adventure bikes by folks who take them into the dust a lot.