Author Topic: Honda CB550 Air Filter  (Read 12291 times)

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Offline kyle750

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Re: Honda CB550 Air Filter
« Reply #100 on: September 05, 2025, 06:28:47 PM »
yep, I do...'75 550F, unrestored, original.

Does anyone own a CB550 with the original PCV setup including all the individual components? And does it work?


Offline HondaMan

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Re: Honda CB550 Air Filter
« Reply #101 on: September 05, 2025, 06:29:01 PM »
We used to replace that 'filter' element with a kitchen sponge cut to size, instead. It prevented the muck from ruining the new air filters, while still meeting the definition of "filtering element", the way the DOT wrote the law circa 1972. It also made the air filters last much longer.
;)
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Offline Deltarider

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Re: Honda CB550 Air Filter
« Reply #102 on: September 05, 2025, 11:21:51 PM »
Kyle, why bother? Honda had been forced to add this blow-by gas filter system on an already existing and succesfull model, the CB500, which had the same frame, so there was not much space to add the thing. Possibly as a consequence the design was poor. General dealer advice in my environment back then was: abandon that blow-by filtersystem altogether and live happily ever after. Those who wanted it nonetheless, had to service it very, very regularly and were advised to have the oil level not higher than halfway the MAX and MIN mark on the dipstick. I remember an in my view stubborn defender of the blow-by gas filter system. Strangely enough he had turned to a foam airfilter element - which btw is inferior from the start. He has stated he had done this because the OEM paper filter element always became moist and he presented the theory that all paper elements did this after a year, which I have proved to be wrong. Mine on a CB500 is over 10 years in its case and filters as ever before.
Because he continued this nonsense about paper airfilter elements getting wet, I started to doubt his motive to go for a foam filter. He argued that is was cheaper as he did not have to replace the paper element every year. The reason I doubted his motive was, that is was very unusual for him to use aftermarket products. He always preferred OEM. He even went so far to buy the OEM sparkplugcaps which are bloody, bloody expensive compared to equally good NGK caps. He was of the opinion that a presumed extra resistance in the ignition secundary circuit was good for spark duration, which is also not proven and now I express myself politely...
At one occasion in 2008 (!) after a long debate, I have reacted in this way:
He had said:
Quote
I have direct experience with filters [meaning OEM paper filters (DR)] becoming more restrictive and unservicable after a year of use.
My reaction was: I know you have. Yours have been peeed on by your crankcase breather tube. I can smell it from here. But you'd rather bite your tongue...  :P
« Last Edit: September 06, 2025, 01:30:56 AM by Deltarider »
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Offline Little_Phil

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Re: Honda CB550 Air Filter
« Reply #103 on: September 06, 2025, 02:24:44 AM »
Does anyone own a CB550 with the original PCV setup including all the individual components? And does it work?
My 550F was set and still is to the original design and I suppose it does work. The bike has done 33k miles. I replaced the filter when I got the bike but have only done about 1500. Took the air filter out yesterday and it was fine.

Offline kyle750

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Re: Honda CB550 Air Filter
« Reply #104 on: September 06, 2025, 03:39:23 AM »
Does anyone own a CB550 with the original PCV setup including all the individual components? And does it work?
My 550F was set and still is to the original design and I suppose it does work. The bike has done 33k miles. I replaced the filter when I got the bike but have only done about 1500. Took the air filter out yesterday and it was fine.

Thank You for sharing your experience

Online jlh3rd

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Re: Honda CB550 Air Filter
« Reply #105 on: September 06, 2025, 04:57:33 AM »
yep, I do...'75 550F, unrestored, original.

Does anyone own a CB550 with the original PCV setup including all the individual components? And does it work?

yes.

Offline UFOwasaband

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Re: Honda CB550 Air Filter
« Reply #106 on: September 11, 2025, 03:37:53 PM »
I'm new around here but...

Reply #9 - #10 I found that you can cut to size and double over 'Frost King Air Conditioner Foam'.  Fits perfect [3/16 thick].  Add ATF, squeeze out and G-T-Go.

The foam can be purchased at big box hardware stores and I picked mine up from a place called Lowe's here in USA.  $2.96 USD.

Offline kyle750

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Re: Honda CB550 Air Filter
« Reply #107 on: September 11, 2025, 05:27:22 PM »
A while ago I sent this photo of a CB550 Air Filter box clip to Kannika and asked if she can make it.  "Easy to do"

The original clips are expensive and mostly in poor condition.  Not exactly sure what type of metal was originally used by Honda (galvanized steel?).  I had 2 trays of flat thick metal laying around that we could use to make the clips.  18/8 Stainless Steel  and Aluminium.  The stainless steel metal was very hard and inflexible so we thought it would be harder to cut and make the bends.  "Aluminium soft but strong"

We fitted the air filter into the box and Kannika took measurements to make the clip.  It only took her less than an hour to cut the thick aluminum, shape by hand and needle nose pliers, and finish by sanding down the sharp cut edges and rounding off the corners. We adjusted the length of the spring at the front curve to create the right tension fit for the air filter.  I forgot to take photos of the finished clip but will try to take photos later today. Looks and works Perfect!

Here is the photo I gave her 

Late Edit:  To be perfectly honest almost anything jammed in between the plastic box and filter should work fine.  This was mentioned by other members and they were right.   
« Last Edit: September 12, 2025, 12:27:38 AM by kyle750 »

Offline jmelche2

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Re: Honda CB550 Air Filter
« Reply #108 on: October 02, 2025, 03:05:53 PM »
I can't get an OE air filter for my CB550 so I ordered one for a 500.  Question is - What do I do with the hose that goes from the rocker cover to the bottom of the air box?  Just leave it?

Offline bryanj

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Re: Honda CB550 Air Filter
« Reply #109 on: October 02, 2025, 03:12:04 PM »
Thats what the 500 did
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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Offline Ozzybud

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Re: Honda CB550 Air Filter
« Reply #110 on: October 02, 2025, 05:54:07 PM »
So I am just catching up on this thread.

Please help me understand what I am missing please.

My 1975 550K1 has what looks like an aftermarket foam reusable filter. The tube goes inside the filter. So the crankcase gasses go directly into the carb intakes
How can it contaminate the filter? Air is being drawn the other direction.

What did the original filter look like?
« Last Edit: October 02, 2025, 05:56:18 PM by Ozzybud »
1976 Z50A PARAKEET YELLOW
1970 CT70  CANDY SAPPHIRE BLUE
1971 CT70H CANDY TOPAZ ORANGE
1972 CT70H CANDY EMERALD GREEN
1973 CL200 CANDY RIVIERA BLUE
1974 CB350F GLORY BLUE BLACK METALLIC
1973 CB350F FLAKE MATADOR RED
1975 CB360T LIGHT RUBY RED
1975 CB400F VARNISH BLUE
1975 CB550 FLAKE SUNRISE ORANGE
1976 CB750F CANDY ANTARES RED

Offline kyle750

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Re: Honda CB550 Air Filter
« Reply #111 on: October 02, 2025, 06:36:58 PM »


My 1975 550K1 has what looks like an aftermarket foam reusable filter. The tube goes inside the filter. So the crankcase gasses go directly into the carb intakes
How can it contaminate the filter? Air is being drawn the other direction.


I certainly am not a CB550, PCV, or air filter expert but my understanding is the CB550 air filter serves a dual purpose.  Filtering air and filtering dirty oil vapors from the crankcase. If your crankcase breather tube is still hooked up to your air box at the bottom and your filter consists of a piece of foam sitting at the top of an air filter box then your air filter is not filtering the crankcase gasses. 

Late Edit:  BTW I really like your air filter clip.  A small piece of wedge shaped wood - simple and looks like it works perfectly!
« Last Edit: October 02, 2025, 06:58:45 PM by kyle750 »

Offline Ozzybud

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Re: Honda CB550 Air Filter
« Reply #112 on: October 02, 2025, 07:12:01 PM »


My 1975 550K1 has what looks like an aftermarket foam reusable filter. The tube goes inside the filter. So the crankcase gasses go directly into the carb intakes
How can it contaminate the filter? Air is being drawn the other direction.


I certainly am not a CB550, PCV, or air filter expert but my understanding is the CB550 air filter serves a dual purpose.  Filtering air and filtering dirty oil vapors from the crankcase. If your crankcase breather tube is still hooked up to your air box at the bottom and your filter consists of a piece of foam sitting at the top of an air filter box then your air filter is not filtering the crankcase gasses. 

Late Edit:  BTW I really like your air filter clip.  A small piece of wedge shaped wood - simple and looks like it works perfectly!

Thank you I designed and built it myself.. lol

The tube standpipe goes to the center inside of the air filter. By design the crankcase gasses are not being filtered by the air filter.

So the original has a hole in it for the tube to enter the inside.
« Last Edit: October 02, 2025, 07:18:13 PM by Ozzybud »
1976 Z50A PARAKEET YELLOW
1970 CT70  CANDY SAPPHIRE BLUE
1971 CT70H CANDY TOPAZ ORANGE
1972 CT70H CANDY EMERALD GREEN
1973 CL200 CANDY RIVIERA BLUE
1974 CB350F GLORY BLUE BLACK METALLIC
1973 CB350F FLAKE MATADOR RED
1975 CB360T LIGHT RUBY RED
1975 CB400F VARNISH BLUE
1975 CB550 FLAKE SUNRISE ORANGE
1976 CB750F CANDY ANTARES RED

Offline bryanj

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Re: Honda CB550 Air Filter
« Reply #113 on: October 03, 2025, 02:40:02 AM »
Yes the tube is inside the filter and theory says it shouldnt wet the filter BUT we all know about theories and take it from a (very) old Honda mechanic they come out wet, black and orrible, probably gases get  around the gubbins at the bottom of the box
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline Deltarider

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Re: Honda CB550 Air Filter
« Reply #114 on: October 03, 2025, 12:00:30 PM »
Every engine 'sneezes' every now and then. And then that paper air filter element catches the wet (condens) oily fumes from the crankcase like a handkerchief catches mucus. ;D
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Offline Little_Phil

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Re: Honda CB550 Air Filter
« Reply #115 on: October 05, 2025, 09:55:47 AM »
Honda fiddled with the length of the pipe that goes up the center of the filter, maybe to address problems. The 550F one (17350374003) is quite a lot longer than the 550K3 one (17350404670)