Topic: Airbox rubber

[Veloman518]

I did a search and didn't come up with a specific answer to this possibly silly question...

I took the airbox and carbs off my K4 because they were a total mess.  Got the carbs rebuilt and all new rubber and everything runs great BUT, the airbox was sheer hell to get back on.  The old rubber was totally shot and hard as a rock so I couldn't really use that as a guide to install the new.  There are 3 ridges on the rubber trumpets that go into the airbox, 2 small with a large one in the middle.  Does that large ring go inside the airbox or outside?  Right now I have it outside and I'm wondering if that's what caused it to be so hard to assemble, since it makes the section between the carb body and the airbox longer, or if it's just poor fitting parts.  Purchased from David Silver spares for what it's worth.

Thanks

[Ace Blackwell]

I’m not an expert on the K4 classification, but it appears that could be a few different models. Can you elaborate on which year and model you have?

[Veloman518]

Sorry, forgot there were other CB's on here

1974 CB750 K4

[Johnie]

The large ring goes to the outside front of the airbox. Smaller ring inside. 

[Veloman518]

Thanks.  That's how I have it set up now, it's just super tight in there.  I also have a weird non-standard carb body that no-one can seem to identify.  The stamping on the shoulder doesn't match any published info I've been able to find.  Wondering if the dimensions are just slightly off.

[Johnie]

Were those rubbers OEM Honda from DS or aftermarket? That could make a difference.

[Veloman518]

Supposed to be OEM.

Carbs are stamped 058A and there was only one other thread in here ever with the same question and no one ever answered it.  Every single part looks and fits like a standard 750 carb and I even rebuilt it with spec jets and other parts.  Runs great now but I hate unanswered mysteries since there is clearly an answer to where these came from and I'm not the only one.