Topic: Help Identifying ORings For Top End Rebuild?

[campbmic]

****Edit**
I found the online listing for the rebuild kit and it gives all the sizes for the orings and what the gaskets are. This info combined with a OEM parts diagram allowed me to figure everything out.
12329-323-000 - Breather Cover Gasket - x1
12391-323-000 - Valve Cover Gasket - x1
91302-001-020 - O-Ring 30.8mm - x12
91303-035-000 - O-Ring 11 x 2.5mm - x3
91319-323-000 - O-Ring 6 x 3mm - x4
91301-200-000 - O-Ring 10 x 1.6mm - x8
91301-323-000 - O-Ring 5 x 2.4mm - x2
91304-286-000 - O-Ring 61.8 x 2mm - x4
91305-323-000 - O-Ring 5.8 x 1.9mm - x1
12251-374-005 - Cylinder Head Gasket - x1
12191-374-000 - Cylinder Base Gasket - x1
18291-390-000 - Exhaust Gasket - x4
12209-333-005 - Valve Stem Seal - x8

I purchased a NE full engine gasket kit for my 1975 CB550. I'm having trouble figuring out which orings Im supposed to use for the oil passages between the cases and the cylinder block (where the base gasket is).

I've narrowed it down to two types of orings that came with the kit. One fits snuggly on the oil port, but does not fill out the entire indentation. The other does not fit snuggle on the oil port, but fills out the entire indentation. See the pictures below. After watching a video it looks like its the one that does not fit snuggly, but just want to make sure, the one in the first picture.

If you look in the picture from top to bottom I have;

3 large (I think the oil passage orings)
4 Medium
3 Small
8 Green
4 Red/Orange XXL (go between the cylinder block and case)
12 Black XL
8 Green plastic nubbies

If anyone has used this kit before, can you tell me what gaskets I will not need to use for the top end rebuild? I'm trying to figure out where everything goes.

I know this is super confusing, I unfortunately don't have anything small enough to measure the orings with a very good accuracy. I'm hoping there is someone who has used this kit before that could offer some advice. Thank you!

[bryanj]

What Bike

[campbmic]

1975 CB 550
Sorry!

[bryanj]

OK then i can look in my very early CB 500 book that gives the sizes for individual O rings and with them being different even if you cant measure them you can at least put them in order.

[campbmic]

That would be awesome Thanks!

[HondaMan]

When not sure: lay the O-ring in its holes and the gasket on the cases. Then measure how far above the gasket that O-ring sits. It must be at least +0.2mm taller to make it seal against the oil pressure there.

More importantly: at the head gasket where those same passages pass thru, the O-rings in your kit WILL be too thin, because the head gasket is to thick. You will either need to mill off 0.020" of the top deck of the cylinders, or get a pair of seals there that are 0.2mm taller than the ones in your kit, or it WILL leak oil, right at those 2 ports.

...this and other stuff coming up in my 550 book...just got the bike yesterday!

[bryanj]

Top cover end cap                   6x3
Tacho drive hsg                     11x2
Head gasket                             5x2.4
Base gasket                           11x2.5
Cam chain tens lower bolt 5.8x1.9

The 8 green ones go on new valve guides when fitting, you dont use them UNLESS you are fitting guides
The 4 big red ones go round the liners at base gasket
The 12 the same are 8 tappet caps plus 4 inlet manifold to head, all the same.
Those sizes are idxcross section

[campbmic]

THANK YOU! I think others might run into this issue too if they get a gasket set without any labels. I was working on the bike yesterday and found the kit online with the details if any future people need it:
12329-323-000 - Breather Cover Gasket - x1
12391-323-000 - Valve Cover Gasket - x1
91302-001-020 - O-Ring 30.8mm - x12
91303-035-000 - O-Ring 11 x 2.5mm - x3
91319-323-000 - O-Ring 6 x 3mm - x4
91301-200-000 - O-Ring 10 x 1.6mm - x8
91301-323-000 - O-Ring 5 x 2.4mm - x2
91304-286-000 - O-Ring 61.8 x 2mm - x4
91305-323-000 - O-Ring 5.8 x 1.9mm - x1
12251-374-005 - Cylinder Head Gasket - x1
12191-374-000 - Cylinder Base Gasket - x1
18291-390-000 - Exhaust Gasket - x4
12209-333-005 - Valve Stem Seal - x8