Inlet and exhaust valve sizes

[Bradders_imp]

Does anyone know the inlet and exhaust valves sizes.

 

[Lord Popgun]

Doesn’t seem to be listed in the service manual.

 

[fritzwilliger_imp]

Does anyone know the inlet and exhaust valves sizes.

Here's what I found:
Inlet valve diameter is 27mm, with a 2.5mm stem;
Exhaust valve diameter is 24mm, with a 2.5mm stem.

I assume that these specs apply to US bikes which have the same 1140 cc inline-4 motor, which is manufactured in Japan.

Link: CB1100 Press Pack

Hope this helps!
-fritz

 

[Bradders_imp]

Thanks 2.5mm stem seems ultra small?

 

[Lord Popgun]

Good find Fritz!! Think I’ll pencil that in my manual.
2.5mm does seem small. The manual says ...measure and record each valve stem O.D. SERVICE LIMITS: IN: 4.960mm (0.1953 in), EX:4.940 (0.1945 in)

It says to ream carbon deposits before checking valve guides using a 5mm reamer and gives the reamer part number. So I’m thinking the stems are 5mm?

 

[fritzwilliger_imp]

Thanks 2.5mm stem seems ultra small?

Agreed! Wonder if somehow the 2.5 mm stem dimension listed refers to the radius instead of the diameter? That would be strange to switch from a diameter spec for the valve head to a radius spec for the stem. Anyone else know what's going on here?
-fritz

 

[peterbaron]

AS per shop manual CB1100 2013-14

Valve stem O.D:
INTAKE : 4.970 - 4.995 mm , (0.1957 - 0.1967 in)
Service limit:.... 4.960 mm , (0.1953 in)

EXHAUST : 4.950 - 4.975 mm , (0.1949 - 0.1959 in)
Service limit :.......4.940 mm , (0.1945 in)

Hope this helps

 

[Lord Popgun]

Hey Peter didn’t I post that 2 posts up?

 

[peterbaron]

Hey Peter didn’t I post that 2 posts up?

Maybe I am crazy = :huh::rofl: but I think you posted in # 5 service limits , not the specs...check please

 

[Bradders_imp]

Thanks guys

 

[Lord Popgun]

Peter, you are right!! What page are they on? I could only find the limits.

 

[peterbaron]

Peter, you are right!! What page are they on? I could only find the limits.

Popgun, you made me working overtime
Cylinder Head/Valves specifications, p. 1-7

 

[Lord Popgun]

Ok, I see that. I did list both the size and limits. But I got them from the Head and valve sectin. But its always good to have it verified, me not being a machinist.