Topic: CB550F Mystery Tube

[The Sovereign Man]

Who can tell me where this is supposed to connect to?



It’s a breather for something, but I’m not sure what or where.

[The Sovereign Man]

And while we’re at it, is there a hose that comes off the bottom of the air box here?



There’s not one. Does it matter? I’m assuming it’s just a drain, right?

[bryanj]

Battery vent tube and yes but its a special end on it

[dazemc]

The sticky that is labeled "Honda general service...." describes battery acid eating away the chain if the vent tube is not properly routed. So that may be important

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[flatlander]

And while we’re at it, is there a hose that comes off the bottom of the air box here?
There’s not one. Does it matter? I’m assuming it’s just a drain, right?

drain, yes. it avoids stuff dripping on the engine case and such. also some unfiltered air may be able to be sucked in if it's just open?
i'd just put a tube on there an route it down. it's a small effort.

[jlh3rd]

the drain tube off the box is #23 in the first pic........ the clear battery tube goes through #12 in the frame pic....but hard to make out. the sticker on your frame shows the routing of the battery vent tube....

[The Sovereign Man]

The sticky that is labeled "Honda general service...." describes battery acid eating away the chain if the vent tube is not properly routed. So that may be important

Sent from my SM-N950U1 using Tapatalk

Challenge accepted Mr Honda!

I did not connect the vent tube.

[flatlander]

the drain tube off the box is #23 in the first pic........

oh it's that one? sorry thought for a moment it was on the plenum.
yes you need it, if your engine breather is routed to the airbox as per the original design.
it has a slotted rubber cap at one end that you're supposed to squeeze from time to time so that the slit opens and lets the cruddy liquid out that comes with the blow-by gases and, if it drips down, accumulates in that tube.

[bryanj]

The missing one is on the plenum and at the "open" end the original is sort of glued with a split so you have to squeeze it to drain any moisture out, supposed to be part of a service

[jlh3rd]

the drain tube off the box is #23 in the first pic........

oh it's that one? sorry thought for a moment it was on the plenum.
yes you need it, if your engine breather is routed to the airbox as per the original design.
it has a slotted rubber cap at one end that you're supposed to squeeze from time to time so that the slit opens and lets the cruddy liquid out that comes with the blow-by gases and, if it drips down, accumulates in that tube.

nope...you're right...i think he means #18 here....available....

[Kevnz]

There is a very comprehensive explanation of this setup by SohRon in the CB550 assembly post. I thoroughly recommend you take a look especially if  you are playing with a 550.