Topic: Uni Foam Replacement which one for 4055?

[rdp2provia]

Anybody replace the foam on their Uni 4055 filter? I have one that the foam has deteriorated... Uni sells bulk foam, not sure which to order though. 30-PPI or 60-PPI?

I could just buy a whole new unit but the box and mesh are fine...


Tanks!

Rick

[Deltarider]

What's wrong with the stock Honda 'paper' filter element? They do not restrict, filter better than foam and can be serviced within seconds. A filterexpert informed me that when airfilter A filters out 99,8 % of the particles and airfilter B 99%, enginewear with B is already fourfold. It's your bike.
On my CB500 they last at least 18.000 kms and don't detoriate over time. That's not bad for a filter that costs only around € 20,-. Foam filters will do on lawnmowers.
Some may find it hard to believe but as a matter of fact paper filters get better in use.
For this and more info: http://forums.sohc4.net/index.php?topic=98901.msg1102737#msg1102737

[rdp2provia]

I'll look into a factory paper filter... haven't seen them around, but honestly I haven't been looking very hard!

[TwoTired]

Just imagine, if you use a flat plate instead of a filter membrane, then 100% of particulate matter will be prevented from reaching the engine cylinders!  What could be better than that?

The simple fact is that paper filters get more restrictive as they collect dust, and they cannot ever be cleaned completely.  They do become better at particle filtration with use as the collected dust further restricts the air path passageways.  But, because it is more efficient at cleaning smaller particles of dust, does NOT mean it is better or more efficient at getting the needed oxygen into the combustion chambers.  In fact, adding dust and making the membrane flow paths smaller create just the opposite effect.   This is why Honda says to replace the paper at one year intervals and clean once at 6 mos.    Your choice, Delta's speculation/rationalization or Honda's engineering/recommendation.  I've already decided which has greater credibility. 

Delta's "experience" is non-characteristic of 99.9% of the SOHC4s in North America.  I sometimes think he enjoys leading us astray for vindictive reasons.  I can believe he has greater air filter life, simply because his bike already has more pre-restriction ahead of the air filter that the N.A. bikes don't have.  (See the restrictor his bike has below.)  If he wants to confuse other Euro owners about air filters who may or may not have that restrictor, that's his choice I guess.

Here in N.A., the paper filters are in the $40-$60 range.  Cleaning a Foam filter yearly (or even earlier intervals) is far more economical than replacing the paper one on recommended intervals.
The Uni filters are cheap enough that a new replacement is pretty enticing, rather than to cobble something makeshift together.

You don't say how old your present filter is.  My Uni's have lasted 15 Years, before foam degradation required replacement.  But, I also use Uni branded cleaner and oil, which I believe is formulated to maximize the foam life.  Other cleaners or oil may or may not hasten the foam deterioration.

I will say that if you live in a particularly dusty area, or you are prone to neglecting the foam filter oiling cleaning process, then a paper type will help your engine wear longer.

[Deltarider]

Two Tired, with all respect but you don't have a clue here. Why is it so difficult for you to understand that the standard filter as Honda fitted is safely OVERDIMENSIONED to allow full flow for a long period of time where you seem to have the idea that it is precisely dimensioned for a clean start and can only perform suboptimal soon after? It is nonsense as is your presumption that it will get bad (loose its fluff whatever that is) in 6 months time. The truth is it doesn't. I'm living proof of that and in Germany somebody recently started a 34 years old 550 that still had it's first filter and he is still using it. All major manufacturers in the automotive field that I know up to today equip their models with cellulose filters. But we have discussed this before. I stress once more that the 550 models in particular are known to get their filters peed on by that silly breather system. Deal with it or don't but don't send people to inferior filters for the wrong reason.
(sigh) And then over and over again this silly reaction with that snorkle. What has that to do with it? Why are you so obsessed with it?

[TwoTired]

Two Tired, with all respect but you don't have a clue here.

If you want to see someone with no clue, look in the mirror. 

Why is it so difficult for you to understand that the standard filter as Honda fitted is safely OVERDIMENSIONED to allow full flow for a long period of time where you seem to have the idea that it is precisely dimensioned for a clean start and can only perform suboptimal soon after? It is nonsense ...

I agree what you wrote is nonsense.  And also takes no notice of the effect on pressure drop vs velocity factors.  Pressure drop across a filter membrane increases with velocity.  Pressure drop also occurs when the filter traps and holds dust particles.  I believe everyone in the world but you has experienced their engine running rich due to inlet restriction be it dirty air filter or application of choke (inlet restriction).

as is your presumption that it will get bad (loose its fluff whatever that is) in 6 months time. The truth is it doesn't.

You can't handle the truth, or recognize it when staring you in the face.  You don't notice it because you already have a significant pressure drop ahead of the filter with that air restrictor.  What fool can't see that restricting the oxygen input to a normally aspirated engine doesn't cause a reduction in power generation when it is most required.

I'm living proof of that and in Germany somebody recently started a 34 years old 550 that still had it's first filter and he is still using it.

Has he won any races yet?  If so, was idle and midrange power setting all that was needed?  How often does he change spark plugs?
How many internet testimonials have proven false?

All major manufacturers in the automotive field that I know up to today equip their models with cellulose filters.

Of course they do. They are cheap to manufacture, install, and replacement costs are passed directly on to the customer.   Dealer maintenance is more profitable via replacment, rather than clean, recondition and reinstall.

(sigh) And then over and over again this silly reaction with that snorkle. What has that to do with it? Why are you so obsessed with it?

What is silly is that you have never figured out what it does and why your machine requires it.  It is precisely the reason why your carbs need #78 mains for the 3/4 to WOT operation.  Restricted inlets and dirty air filters behave the same way as applying choke for fuel enrichment.  However, if you never read that in a magazine for your education, then of course it will never be true to your imaginative physics interpretations.

Please do explain to us how the pressure drop across a filter membrane (or any) restriction is effected by an increase in air velocity.  What does your magazine education say about that?

Then tell us why adding dust particles to a filter membrane avoids increasing the pressure drop across it.   I'd be entertained by your imaginative non-scientific answer.

[Deltarider]

Then tell us why adding dust particles to a filter membrane avoids increasing the pressure drop across it.   I'd be entertained by your imaginative non-scientific answer.

I told you already. The standard filter has more than enough reserve like any cellulose filter in any car or motorcycle. I remember Suzuki back then had models with foam filters. Customers didn't like them and as a result often valued Suzuki as the somewhat 'cheaper' brand. The type of filter that you favor, you will not find in Europe.
Dave Silver offers a good imitation cellulose filter for the 500 as well the 550 for no more than € 18,84 or $ 24,13. If you must for the 500 you can still obtain the genuine Honda part for € 28,26 or $ 36,20.
That's about the same price as back then after indexation ofcourse. And check this site. You'll still find the different CB550F and CB550K3 filters. http://www.cb-4zylinder.de/cgi-bin/shop/__CB-550-K+F/Verschleissteile/_04.08.html
I find these prices reasonable and personally I have good experiences with aftermarket cellulose filterelements. For the rest, I hope you will forgive me but I won't be dragged again in your trap of creating mist and making things as complicated as possible. For me it is perfectly clear and I have already presented dynodata to proove it. I just find it irresponsible of you that you direct people to inferior filters for the wrong reason. Inferior from the start and maybe you should read the question again hat started this thread...
Then this. When I pass on information that I have gathered elsewhere I have the decency to tell so and what my source is. Do you always? I'd be entertained by your answer.

[dave500]

[Deltarider]

Here is my collection of old genuine Honda airfilterelements. They all came in a simple carton box (no plastic bag) and are still good.

[Deltarider]

And here's my collection of aftermarket airfilterelements. Mine came in carton box (no plastic bag) and are still good. I used to change my filterelements for a new one before I went on a 10.000 kms holiday. Ofcourse I've kept the used ones and now I have a nice reserve in the basement. Personally I've not experienced a difference in quality between the genuine Honda and an aftermarket filter but that's just me.

[Stev-o]

I didnt know used air filters were collectable?  Dave - do you have yours?
I have one from my RD350 that I just replaced, I may put it on eBay?

[dave500]

I must confess steve I do have a good used one but im not going to make a habit out of it.

[rdp2provia]

Didn't mean to start a Filter war!

My present Uni Filter came with a bundle of airbox parts, as I am retuning the bike to bit more of a stock setup. I'm not sure how old the filter is but I purchased the UNI Maintenance Kit and cleaned it once and the foam started to rip and crumble. I appreciate all the information on this board and especially the information TT has shared with me and other on the subject of carbs, cleaning them, rebuilding them, etc.

I do have a UNI filter foam update for anyone interested, I got and email directly from their sales department stating BF-4 and BF-1 are the bulk foams with the same spec as a Un-4055. They are sheets 12"x16" and are (60PPI) and (65PPI). Looks like Amazon carries them.

I'll be ordering a sheet of BF-4 and giving it a shot in the 77 550f

Best,

Rick

[Deltarider]

Total time I've spent on servicing my airfilter by using the real thing is 6 X 10 seconds. One minute in 35 years. That's not bad. Never ever had to think about it, never any doubts. Priceless. I rest my case.

[dave500]

that frees up so much more time for you to say,have a wank or something?

[Deltarider]

Forgive me. 'Have a wank', what does that mean? I'm not a native speaker.

[dave500]

umm,id rather you google it,hang on let me do it for you,google that is!
http://lmgtfy.com/?q=wank

[jamesbekman]

I love you guys.

[dave500]

and we love you to.

[socal1200r]

If I could replace the stock paper filter on my '79 CB650 with a Uni foam filter, I'd do it in a heartbeat (hint, hint, anyone have the Uni part number for that?!).  These air filter "wars" have been going on as long as the "wars" about synthetic oil versus dino oil and tires.  I used to have a '95 Moto Guzzi 1100 Sport (frame #2, I should've kept that bike!) that had a full Staintune exhaust on it.  I had the carbs rejetted, and fitted some K&N pods on them.  Bike ran fairly well, all things considered.  Found some dual-stage Uni foam filters for it, slapped them on, then had to adjust the fuel/air screws because the bike would die at idle.  Now I forget which way I adjusted them, but in any event, the bike ran better with the Uni filters than with the K&Ns. 

On my '79 CB650, I'm not interested in running individual pods on each carb, but would entertain the thought of replacing the stock paper filter with a Uni foam filter.  Right now, I have the airbox lid off, and fabbed up an aluminum strap that goes between the upper and lower mounting bolts, to allow more air to flow into the carbs.  Bike actually runs better with this mod, isn't as hard to gas/clutch it when starting off.  Compare the small airbox lid opening with a more or less open airbox intake now, and it's flowing a lot more air.  But still, if I could find a Uni foam filter to replace that stock paper one, I'd be all over it.  Another trick I've learned is to use regular old cooking spray on those Uni foam filters.  Just spray the outside, rub it in, let soak for a few minutes, then dry off with some paper towels, and you're done, no need for that expensive Uni filter spray.  And don't use olive oil spray, that stuff is WAY too oily!

[dave500]

ill chuck a shrimp on your engine and itll be cooked in about 50 miles?