Topic: Stock Airbox pieces

[Shlippery]

I am putting back together a 76 CB550K and am going through all the parts I got with the bike (bike was very cheap and a lot of the parts were off of it in bins). I am now realizing the only pieces of the air box I have are the main box and plastic plenum, the boots, and a new cartridge. I was looking at an exploded diagram and it looks like I need quite a bit. My question is can I just run the paper cartridge and plug the hole in the bottom of it or has anyone done this? That would remove the parts in the attached image that to me seem like part of a pre-filter? I have the retaining spring for the paper element but none of the piece the plug into the bottom of it.

[newday777]

Welcome aboard the forum Shlippery
I don't have a 550 to confirm but I think I've read of some using a scotchbrite pad as a filter at the bottom.

[Shlippery]

Do you know the purpose of that assembly that sits in the bottom? Can’t seem to find much info or photos online or in my Clymer

[bryanj]

Its to filter oil from the breather at top of engine

[bryanj]

In asnswer to your other question yes you can BUT use a 500 air filter, run the top breather out to atmosphere at crancase and plug the nipple on bottom of case

[Shlippery]

In asnswer to your other question yes you can BUT use a 500 air filter, run the top breather out to atmosphere at crancase and plug the nipple on bottom of case

Ok thanks I will look into this. Just to clarify you mean the nipple at the bottom of the air box?

[bryanj]

Yes, the one the breather is supposed to go to, you can in theory leave it open but water might get in

[Shlippery]

Yes, the one the breather is supposed to go to, you can in theory leave it open but water might get in

Sweet, sounds like that is the route I will go or maybe a Uni 500/550 foam filter and just leave the bottom plug in it. I suppose I could just run a small pod off of the crankcase breather to keep any junk from getting inside. Thanks for the knowledge, was hard to decipher just from the exploded diagram. It would be like ~$150-200 dollars to source all those pieces from eBay (which is almost half of what I paid for the whole bike) so if I can omit them I would prefer that. I kind of figured they weren't critical since people run pods which wouldn't have any of that.

[Deltarider]

Foam filters are inferior to paper filter elements. The OEM CB500 airfilter element lives forever (more filter area than a CB550 OEM!), costs around $ 33,- and can be replaced within 20 seconds. Your choice.

[rotortiller]

Enough 4 stroke bikes come factory new with dual layer foam filters. They work fine and are often serviceable. I wouldn't think twice about using one inside the airbox if available.  Paper filters are fine too.

[bryanj]

Either work fine IF FITTED BY FACTORY but changing from paer to foam alters the amount of airflow

[MauiK3]

I guess I'm old fashioned and somewhat anal about air filters. I run stock. I would stay up nights thinking about all the nasty stuff being sucked into the poor pistons and cylinder walls, rings, grinding away at the moving parts.
I'd find the parts

[Shlippery]

I guess I'm old fashioned and somewhat anal about air filters. I run stock. I would stay up nights thinking about all the nasty stuff being sucked into the poor pistons and cylinder walls, rings, grinding away at the moving parts.
I'd find the parts

Agreed, I am still running a stock airbox and filter just won’t be using the extra element sits in the bottom. The filter will still have a stock fit

[Shlippery]

Foam filters are inferior to paper filter elements. The OEM CB500 airfilter element lives forever (more filter area than a CB550 OEM!), costs around $ 33,- and can be replaced within 20 seconds. Your choice.

I just ended up ordering a stock CB500 one from 4into1.

[rotortiller]

Either work fine IF FITTED BY FACTORY but changing from paer to foam alters the amount of airflow

As the factory paper filter ages the air flow changes, however the bike keeps on running just fine. Just because it came with a paper filter does not mean something else cannot be safely employed in the airbox, that is just plain silly. Look at the front tires, brakes and oil the things came with. My car came with a paper oil filter with Toyota written on it, I now use synthetic Mobil1 oil filters.

[bryanj]

Having, over many years, worked on bikes with standard and "modified" air filters i can hoestly say that no modified system worked as well as the standard paper, also the only Honda that ran worse with old air filters was the CX 500 where the mpg would drop off markedley and come back with a new filter

[Tracksnblades1]

Foam filters are inferior to paper filter elements. The OEM CB500 airfilter element lives forever (more filter area than a CB550 OEM!), costs around $ 33,- and can be replaced within 20 seconds. Your choice.

Good advise: 😇. The one Honda warrantied it with..😇

We have 6 Honda CR dirt bikes ranging from 85cc to the Holy Grail 500cc.
They all have dual foam oiled filters…Honda recommends servicing the CR’s dual foam air filters after every ride..
7 to 8 hours is about the longest service intervals you’ll find recommended for competitive CR operation.

[Deltarider]

A filterexpert (Mann, Audi) once informed me that when airfilter A filters out 99,8 % of the particles and airfilter B 99%, enginewear with B is already fourfold.
For more info on how paper airfilter elements actually work and why there is no change in performance over time, not until the very end of its lifespan: http://forums.sohc4.net/index.php/topic,98901.msg1102737.html#msg1102737

[rotortiller]

The 500/550 guys that use them seem to approve, from the 4 into 1 site at least. I have dual layer foam on Kawasaki triples, Yamaha R6 and YZs, and Betas. Also use K&N on a triple in the airbox and they all work fine and trap dirt. Words are cheap experience not so much. My CB750s use inexpensive paper Emgo air filters which are not a Honda brand, those too are fine. Many people with decades of quality wrenching experience have come to appreciate product diversity and usage. For special applications foam filters sometimes offer a fabric sock, put it over the filter or you could put it elsewhere lol

[extrafunky]

Agreed, I am still running a stock airbox and filter just won’t be using the extra element sits in the bottom. The filter will still have a stock fit

If you use a 500 filter on a 550 airbox, you will need a spacer in lieu of the missing recirculator pieces.