1978 - CB750K Four - Need New Valves - Where To Buy?

[Thompkins]

Hello,

I need new valves for my CB750K8.

Does anyone know where I can buy new ones? Part # 14711300015 and 14721330015

Also, will part # 14711300005 or 14721300005 from 1969-1977 work?

Thank you.

Phil

 

[Loose Chain]

Have you looked into the price of a rebuilt cylinder head ready to bolt on?

 

[brettp]

To answer your parts question, as long as the first two sections of a part number are the same, the parts are interchangeable. The last three digits are specific to a manufacturer or supplier.

 

[Hisvett]

Check out this place; Cycle Exchange They have valves and can rebuild heads. Lots of other power adders too.

Good luck

 

[Thompkins]

Breaking News....

I have found an answer.

If you have a 1978 engine I have confirmed that the 1969 - 1976 Intake and Exhaust valves are compatible with the 1978 CB750K SOHC Honda as follows:

1. The 1978 OEM Valve Cotter part # 14781410000 must be replaced with 1969 - 1976 OEM Part # 14781551000
   
   
2. The 1978 OEM Valve Spring Retainer part # 14771410010 must be replaced with 1969 - 1976 Part # 14771551020
   
   
3. The 1978 OEM Intake and Exhaust Valve part # 147111300015 and 14721300015 must be replaced with 1969 - 1976 Part # 14711300005 and 14721300005

1. Valve Stem Seals remain the same.
   
   
2. Valve Springs (inner and outer) remain the same.

 

[Loose Chain]

Sounds like a pretty large expense. Why not buy another head? Why are your old valves so bad?

 

[Thompkins]

It is a large expense but something I am willing to do considering all of the other work I have done to the bike. I have another head if somebody else is looking for one.

 

[Loose Chain]

If you have another head why can't you use it?

 

[madmtnmotors]

Breaking News....

I have found an answer.

If you have a 1978 engine I have confirmed that the 1969 - 1976 Intake and Exhaust valves are compatible with the 1978 CB750K SOHC Honda as follows:

1. The 1978 OEM Valve Cotter part # 14781410000 must be replaced with 1969 - 1976 OEM Part # 14781551000
   
   
2. The 1978 OEM Valve Spring Retainer part # 14771410010 must be replaced with 1969 - 1976 Part # 14771551020
   
   
3. The 1978 OEM Intake and Exhaust Valve part # 147111300015 and 14721300015 must be replaced with 1969 - 1976 Part # 14711300005 and 14721300005

1. Valve Stem Seals remain the same.
   
   
2. Valve Springs (inner and outer) remain the same.

Yes, this is a common "upgrade" due to the larger cutout in the earlier valve stem for the valve cotter as well as a wider angle where the earlier valve cotter seats in the valve spring retainer. Some of the 77/78 K and especially F models have failed when the valve cotter actually pulled through the valve spring retainer. Not a very common problem, but it has happened. The swap is easy, you just have to use matching valve/cotter/spring retainer components, and of course new guides are always in order when replacing valves.