Topic: Breather Filter Replacement

[storm]

New member and proud new owner of a 76 550F Super Sport!

I have been reading a lot of posts and gathering great info but haven't got a clear answer on one important question I have. Where can I get a replacement for the element that goes inside of my breather in my airbox? I have a stock airbox with the paper filter and just ordered a UNI to replace that. But the breather piece only has a rubber seal at the bottom then a small steel screen. And when I remove the breather there is another small steel piece that just lays there that also has no filter attached.

I have read about maybe using a scotch pad and cutting it to shape. Will this work? And how would I get that filter to stay in place, just place inside the breather tube bottom?

I can attach pictures when I get home tomorrow if need be to clarify. Any info would be of great help. Thanks. And I'm sure I'll have more questions as time passes.

[TwoTired]

The breather filter function is to keep particulates from entering the intake, and provide a place for condensation to be trapped.
The foam filter element is discontinued from Honda (so I'm told). What you should get is oil and gas resistant open cell foam about 1/4 inch thick.  Cut it to fit inside the rubber seal of the "breather piece".  Scotch brite can "work".  But, it really only traps very large particles, rather than the fine ones the original would.

Be aware the lower filter box drain hose should not be open ended.  It is supposed to have a cap with a slit in it, so when you pinch the cap, water can drain out, yet it will block air coming in.

[SohRon]

Here's what it looks like:



3" X 4" x 1/4" medium-density open cell polyurethane foam, kind of like the stuff used for the air filter in your lawnmower. If you have the rubber seal, that's a real coup as they're hard to find.

[mono]

Neat - i always wondered what that seemingly useless thing was for lol.  Now i know that it needs foam

Sent from my SPH-L710 using Tapatalk 2

[madmtnmotors]

kind of like the stuff used for the air filter in your lawnmower

I actually use a lawnmower air filter. They're cheap and easy to cut to fit.

[SohRon]

Neat - i always wondered what that seemingly useless thing was for lol.  Now i know that it needs foam

It's a wet filter, and the Honda Shop Manual wants it to be lightly coated with ATF then squeezed dry; again, just like the filter on your mower.

[storm]

Thanks TT and Ron. Yes I do feel lucky I have the rubber trim. And I'm not sure if I have the cap on the end to prevent the air coming in. I will have to cap that.

And I was just going to ask about soaking it with ATF, so thanks for already answeinf that too.

[madmtnmotors]

And I'm not sure if I have the cap on the end to prevent the air coming in. I will have to cap that.

I think the cap is to prevent any oily mist from collecting beyond the discharge point. I leave mine open and have not noticed any oily spray. In lieu of a cap, you can use a bolt, or anything else of the appropriate size, if you prefer to drain this in a more controlled fashion.

[TwoTired]

And I'm not sure if I have the cap on the end to prevent the air coming in. I will have to cap that.

I think the cap is to prevent any oily mist from collecting beyond the discharge point. I leave mine open and have not noticed any oily spray. In lieu of a cap, you can use a bolt, or anything else of the appropriate size, if you prefer to drain this in a more controlled fashion.

The filter box chamber has negative pressure during run time, which is applied to the breather assembly.  If the drain tube is left open and free to flow, that lower open tube bleeds off the negative pressure that would otherwise be applied to the crankcase.  Further, the negative pressure and open tube creates an inflow of air and debris (from near the road) that what would otherwise be be blocked from entry.  The foam element filter will or should collect all this, but, being small, will need more frequent cleaning attention.

One of the beauty aspects of the slit cap on the end of the tube, is that it will allow water to drip slowly out when the engine isn't running, while still blocking air (and debris entry) during run time.

Honda called that cap on tube assembly a "Pinch tube" in the maintenance manuals.

Many systems only work as designed when all the parts are still in place.

Cheers,

[mono]

mine works without the pinch tube in place(or the foamy piece), but i'm curious to see if it works *better* with them!    i'll have to add these to my list of things to buy this winter.

[TwoTired]

mine works without the pinch tube in place(or the foamy piece), but i'm curious to see if it works *better* with them!    i'll have to add these to my list of things to buy this winter.

Um...define "works".

With tube #6 open, the crankcase can't be properly evacuated and "stuff" can get sucked up into the breather unit.  With out the breather foam, the sucked in "stuff" by passes the air filter and goes directly into the carb and engine cylinders.

What is in the air that is being breathed in has an impact on how long breathing is possible.

Cheers,

[mono]

^ yes, i understand that now...    on the "fix" list.

it's the way the bike came.  it's also my 1st bike.  cut me some slack, grumplestiltskin.     this is why you're the experienced veterans and we're the noobs! 

**edit -- i take it back.  it's not the way the bike came.   there was no hose on it at all when i got it.  i put one there!  just had no idea there was that little valve-a-majig at the bottom.  i'll fab something up before i ride again.

[SohRon]

i'll fab something up before i ride again

A simple plug is all you need. This is a door panel clip from a VW Beetle. Whatever works; just plug it up well and don't forget to drain it occasionally...

[mono]

Lol that is seriously the best visual aid I've seen on this forum.   I'm hitting the hardware store shortly, but if i see a VW on the way I'll snag a door clip

Sent from my SPH-L710 using Tapatalk 2

[storm]

i'll fab something up before i ride again

A simple plug is all you need. This is a door panel clip from a VW Beetle. Whatever works; just plug it up well and don't forget to drain it occasionally...

My #6 tube that comes out of the airbox only extends about 3" and is a total pain in the ass to get to. The only access is from the right side cover and even with small hands I cannot properly get in that space to cap the end. Should this tubing come down as your picture shows even on my 550F? If it should extend that far how would you recommend fixing that issue? Thanks.

[cougar]

storm ; If you've got a local junk yard (automotive) that will let you walk around and look your in luck. A lot of times you can find one on the bottom of the A/C box (there for the same purpose of water drainage) that's bolted to the firewall and sometimes on the older GM products you could find them on the blower motor. Just a thought.   ...cougar...

[SohRon]

Here's a pic showing the special tip, with the hose attached to the air filter/element case

The hose on my '74 K model is just about 11" long, with the tip. I'm not real sure about the "F" bikes; since you have the exhaust kind of in the way, this hose may route a little differently. You could try routing it as shown above, with the tip through the overflow tube bale, and see how it works out.

This filter case drain tube is no longer available, but the longer plenum ("Chamber NH1" for purists  ) hose can still had from David Silver Spares, BikeBandit, etc, etc...  you can just cut it to length
 

One thing to be aware of is that the plenum hose has a foam filter in the end of it; you'll want to remove it when adapting the hose as a filter box drain, as shown below

And, of course, you'll want to make sure it's tightly plugged...