Airbox to rubbers sealant

[Tazaud]

Hi everyone,

Noticed when fitting the airbox on the  cb400f that there is a sticky sealant residue around the rubbers where they connect to the airbox.
Is this something that is needed and if so where can it be purchased, or can a normal silicone sealant be used?

Thx in advance

Craig

[kevski]

No! There should not be any sealant on any joints on the intake side or carbs, there is a chance it can get into the motor and cause problems and damage. Whoever put it on in the first place needs their tools removing.

[Tazaud]

Strange as I was the first person to ever take the airbox off from new. the bike has done less than 6k since new and the 2 previous owners are family members that wouldnt have even touched it.
There is definately something on there. its still tacky, almost like a greasy brown sealant.

[Clem2112]

Between carbs and inlet manifold?
Maybe something to help with assembly that doesn't come off easily?

[Tazaud]

Its on all 5 rubbers where they connect to the black plastic airbox. the 4 that go to the carbs and the one that goes to the air filter (oval rubber)

[JamesH]

From my experience Honda did use a form of adhesive between the airbox and airbox rubbers (so on the external surfaces so very low chance of ingress into the engine). However, I've yet to work out what it is..

[Bryanj]

James is correct as the rubbers are "glued" into the airbox. Used to use Evostick to glue the rubber rocker gasket into the DOHC motors--especially the CBX, was also a majour use for the Honda "Blue Book" Manuals (hold them down till the glue set!!)

[kevski]

I have never come across this or any evidence on any of my bikes including my old 350f or 500K3.

[Tazaud]

im wondering whether some clear silicone sealant would work, obviously only on the outside edge.

[Clem2112]

Surely the rubber inlets design means they seal well enough  without needing any packing adhesive?

The airbox rubbers do tend to turn a bit when the carbs are pushed past so maybe it prevents that happening.

[Tazaud]

Cheers Guys, Will see how she runs, If it needs it then there is probably some pre-war bostick in the old mans garage.lol

[AshimotoK0]

I would think the stuff to use would be semi-flexible, water clear or black,  epoxy resin ...  which is resistant to fuel and excess on the visible bit of the airbox can be wiped clean with isopropanol before it cures.  I agree....  my original 400/4 definitely had some sort sealant on the airbox to carb rubber interface.

[Bryanj]

Having stired my memory from the colour and way the original peeled off i think it must be something like evostick