Topic: Cb400 seals

[malcolmgb]

I'm about to start rebuilding the top half of my engine now, but I'm a bit puzzled over seals. I got a complete gasket set with the bike, part # 06110-377-010, I have attached a picture of the seals in it, can someone tell me where they go and am I any missing to fit the barrels to the crankcase and then the head & camcover.
A -
B -
C -
D -
E - Cyl Head Exhaust
F - Inlet Valve
G - Valve Guides (green rubber)
H - Cylinder Liners
I -
J -

[Bodi]

A: Valve adjusting covers
B: intake adapters
C: Oil flow control orifices
D: Head/barrel dowels
E: Exhaust port/header
F: Valveguide esals (inlet only)
G: Valve guides (only if replacing guides, optional even then)
H: Barrels
I & J: There's an O-ring on the cam chain adjuster screw and on the bolt that covers the top hole on it, these could be them.

Still, where are the O-rings for the oil dipstick and for the 2 oil gallery plugs?

[ttr400]

I&J look like the o-rings for the cam oil feed pipes.  dipstick and gallery o-rings only come in the bottom end gasket kit.

Kevin

[supersport_CB400F]

I got this letter with my gasket set from DSS, you my want to check the parts book.

[Bodi]

But the cam oiler tube O-rings should be two the same size?

[JHansen]

Oh boy... malcoms question has giving me a delima-

I had the machine shop do a valve job on the bike for me when the re bored my barrels.

I did not replace my valve guides as they said they were just fine.

Problem is this- they gave me the head back with the valves already in place, and I did not disassemble for any reason before putting back on the bike.

So, I have no idea really if my valve guide seals are in place. When they gave it back they did not say I needed to obtain new ones. Possible they reused the old? They said the head was ready to just bolt back on. If these things are missing, what are the symptoms? Burning oil? I've been running the bike for a few days, and it is not blowing any blue smoke that I can see. 

Do I really have to pull the head off and check this out? Oh boy- please advise!

[malcolmgb]

thanks for your feedback on this guys, I think I&J are the camshaft/rocker feed seals, I had forgot about them, the parts list does show them as different sizes, I will measure the seals tomorrow to confirm.

[Bodi]

Right, they are different sizes so you can't put them in wrong I think. Reversing them would spray oil in the wrong direction on both sides and you wouldn't have any cam oiling.

The valveguide seals would best be replaced after 30 years, but the original ones may be fine. It shows up as a bit of smoke after engine braking... the high manifold vacuum then sucks a bit of oil down the valveguides which burns off when you go back on throttle. Of course, bad rings does this too... I wouldn't worry unless you see a lot of smoking or get fouled plugs, very little oil can get through the tight valve/guide clearance anyway.
If a wet/dry compression test shows good rings and valve seating but you still get that puff of smoke, then guide seals would be the suspect.