Topic: CB550F Air filter box

[Philip L]

Hi I have just purchased a restoration project, it’s a 1975 CB550F. It’s missing the stock air filter box assembly. Looking at what’s for sale they all look the same but there are different part numbers on later years when checking the parts catalog on CSMNL. Does anyone know if there are differences that would prevent fitting. Plus does anyone have a stock air filter box assembly.

[Little_Phil]

If you mean the actual box that the air filter sits in there is a difference in that 500s and maybe early 550s did not have the engine breather recirc system where gases are re-fed to that box. Actual late? 550s air filters have a hole underneath that is part of this.

[TwoTired]

I think there are only two filter boxes.  Early style without the engine gas recovery parts. The air plenum and carb couplers also have two versions for early carbs and the later PD carbs.

The real pain is getting all the fittings, brackets, spacers, and grommets to properly mount the box to the plenum and bike frame.

[extrafunky]

I think the air filter box fitment is not really an issue when you mix & match parts from different years including 500s. All 550s already have the breather recirculator. Main difference is the lid. Ks have a tool tray, Fs have a scoop.

I have a K0 and decided to use a 500 filter box so I don't have to deal with the breather recirc as those parts seem pretty hard to find.

[Stev-o]

Looks like he has an airbox for sale...

http://forums.sohc4.net/index.php/topic,191297.0/topicseen.html