Topic: cb400f - Top end gasket set piece identification

[lohebohi]

I purchased a top end gasket set and there are a couple of things I am not positive of what they are for.

I figure some people may run into this in the future so I labeled all of the parts and I want to make a list of all the pieces.

I have updated my list to include information provided later in post.

1.  Oil spray bar right hand side.
2.  Oil spray bar left hand side.
3.  Oil control orifice valve seals (where it always leaks oil from the head gasket on left side).  Around the things that look like headphone jacks.
4.  Valve guide seals, for teh intake valves.
5.  Valveguide O-rings (only if you replace the guides, optional even then)
6.  Carb adapter O-rings, between the 4 carb boots and the head.
7.  Exhaust port to header packing.
8.  Tappet hole cap seal.
9.   Breather Cover Packing.
10. Cylinder Head Cover Packing.
11. barrel O-rings, where barrels protrude from bottom of cylinder.
12. Base gasket (between cylinder block and main case).
13. Head gasket.
14. Pair of things with no number between 1 and 4, look like 2 dowel pins between head and cylinder, front corner area.

[Bodi]

First, your list numbers seem a bit mixed up, so I'm using the ones on your picture.
Second, replies should go here to the board so people can add and correct information and there aren't multiple identical answers. PMs only get seen by you.


1. Not sure, probably for the tach drive (only thing there's just one of)
2. ditto.
3.  oil control orifice valve seals
4.  oil spray tube support blocks
5.  valveguide O-rings (only if you replace the guides, optional even then)
6.  carb adapter O-rings
7.  exhaust port to header packing
8.  Tappet hole cap seal *
9.   Breather Cover Packing *
10. Cylinder Head Cover Packing *
11. barrel O-rings (only if you replace barrels)
12. Base gasket (between cylinder block and main case)
13. Head gasket
14. There is no #14 in the picture. There is a pair of things with no number between 1 and 4, I think these seal 2 studs.

* your answers

[lohebohi]

11. barrel O-rings (only if you replace barrels)

It looks like one of these O-rings has popped out of it's home.

It also looks like the other ones will be easy to damage when I scrape off the old base gasket.

[Bodi]

I was wrong again. Those O-rings just sit in that groove.

[bryanj]

No 4 is valve guide seals as there are 4 of them you dont get the support blocks in a gasket set
No 1 There is no "O" ring on the tach drive and there should be 2 for the oil spray bars which are different sizes!!( Nos 1 & 2)
No's 3 & 14  one set go at base gasket level one set at head gasket level to seal the oil feed passage to the cam

There are two special head nut washers 90442-377-000 that i would recommend replacement of as well, these go under the two "odd" nuts

PS those "O" rings on the barrel base regularly come out on dissassembly and a re an a**^ole to get in.

[Bodi]

Ah ha! I was wrong again! Good guesses though
I forgot about the oil tube O-rings being different sizes so you can't put them in backwards, and couldn't think of anything with just one seal. The tach drive does have an oil seal that likes to leak.
Only the intake valve guides have seals, you can get aftermarket exhaust guides with seals if you really think that's important. Not a bad idea if you are doing valveguides anyway, the aftermarket ones cost about the same as Honda OEM and are arguably better quality.

[lohebohi]

I have a dumb question.  Are the exhaust gasket seals still in my cylinder head.  I think they are, but before I do anything drastic (they are not coming out easily) I wanted to make sure there was not a lip cast into the head.

Also about No. 4, the intake valve guide seals;  Does anyone know why there are no valve seals on the exhaust valves?  Motorcycles continue to befuddle me.  Are the intake valves not pressed in, do they slide out for quick replacement???