Topic: 77 550F Airbox ports

[Ace Blackwell]

I have a 77 550F.  I’m getting my airbox unit back together as part of my carb installation.   It’s the first time it’s been on the bike in 20 years.   I can’t remember where the connections go.  The broken port had an intentionally plugged hose attached.  I still have the hose with the plastic screw inserted.  This matches some diagrams I’ve been able to find.  I’ll just patch this hole as nothing went to it that I can tell.   That leaves the one port on the filter box and the one port on the air chamber section.  I assume the remaining port on the filter box is for the breather hose but I don’t know that for sure.   And I don’t have any idea what the port on the air chamber is for.   Does anyone else know?

Thanks
Ace

[Scott S]

 That hole on the filter housing looks like damage and isn't stock. I'd patch it. The nipple on the filter housing is for attaching the hose from the breather on top of the valve cover. It routes down between the carbs/manifolds, under the carbs and to the nipple.

 The one on the plenum is a drain. That hose has an end with some foam or a pinch type end, to let spilt gas escape but stop debris and unfiltered air from getting in.
 The early plenum didn't have that nipple/hose.

[TwoTired]

 You sure that's from a CB550?

The elbow on the side routes up to the engine breather.

There should be a low point drain, and a pocket for the metal water/oil separator in the bottom of the box.
The low point drain hose has the slit/pinch tube end, allows water to drip out and block incoming dirty air.

The plenum box is a drain incase the carbs overflow gas and fill the chamber.  Originally it had a molded reduced diameter hose (to about 1/8 inch opening, with some open cell foam stuffed in it to block debris and insect from entry.

Below is what you need.  The tray/air box cover is for a K model, the F had a curved horn atop the filter case, as in the second pic.

Cheers,

[Ace Blackwell]

Thx TwoTired. Yeah I’m pretty sure. I’ll double check tonight but it had 550 molded into the side.  I have the same air induction as your stand alone picture. What I don’t have is the 2nd pinch tube, the 3 brackets and the screen/gasket/sq filter for the bottom. I’ll work on those next. Thx again.

[CBDee]

See Sohron's "cb 550 assembly manual" in the maintenance section for more information.