Valve diameters lenths and other differences K0 vs. K1-5

TeaLow

TeaLow

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Hello,
I'm asking because I'm searching valves for my empty K0 head.
Couldn't find anything on the search function and on the internet.

What is the difference between the K0 valves
I: 14711-283-000 / 14711-282-010*
E: 14721-283-000 / 14721-283-010 / 14721-283-020*
(My engine is #1025820, so I think I need the valves marked with a *)

and the K later valves
I: 14711-292-000
E: 14721-292-010

I unfortunately cannot measure my K1 and K2 valves, because my heads are still assembled.
First I want to complete the rest of the engines due to my limited space.
Nevertheless I want to start finding the missing parts for my K0 engine.

Thank you very much in advance!

Greetings,
Thilo
 
@jensen , do you have any advice, how to identify the correct valves? Or can I just use any K0-K5?
Best regards!
Thilo
 
Amannl said:
Yes, I should have mentioned that it was from the ’68-‘75 manual
Click to expand...
Just wanted to be sure we were looking at the same thing. I've never personally used or worked on a 4 speed head so I've never had the chance to compare, but the differences seem smaller than I expected.
 
Thanks. That are just the stems. 7mm. Obviously all the same.

But what's with the "big part" (don't know how you call it) and the lenghts?

The ones I have are:
I:38/100mm
E:33/96,5mm
I think the are from a later head. They did not belong to the K0 parts, but came loose with the K1 engine

IMG_20250525_165453447.jpg
 
jensen said:
No, they differ in diameter, let me check which one (ex- or intake valve)
Click to expand...
Hello @jensen ,
did you already have the chance to have a look?
I'd really appreciate that.
Thanks a lot in advance!
Best regards,
Thilo
 
It wasn't clear to me which information you were looking for. I saw others answering the question, so I thought you had all the info you needed.
I'll measure, tomorrow, the valve disc diameter and the total length of the valves of a CB450 K0 and K1. I do remember that the very early K0 heads had a different valve disc diameter then the later one's. What is the engine number ?
 
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Thank you very much!!!
Mine is a later one, 1025820.
Yes, through the K0 they had two different intake and three different exhaust valves according to the parts list, and all K later got also a new number then, but then no more changes.

Thank you!!

You're from the Netherlands, aren't you?
I'm from Germany, Ruhr area.
 
Yes, I'm from the Netherlands. The Ruhr area is a very large (heavy) industrial area, with a few large cities (for non-Europeans, the Ruhr area is named after the river the Ruhr). It's more or less comparable with the "Manufacturing Belt" in the Northeast and in the state of West Virginia.

Where do you live ? Close to Düsseldorf ? I'm on a regular basis in Düsseldorf, at one of our Costumers.
 
I live in Bochum, it's right between Dortmund and Essen. Mostly I only go to Düsseldorf Airport. It's the nearest. I've a friend in Hillegom near Amsterdam. Sometimes I'm there when we are on vacation in the Netherlands.
Great country, very nice people. But became a bit expensive in the last few years.
So we are checking alternatives. UK, Mallorca, Djerba. All are cheaper including all than a Chalet without anything in Netherlands.
That was different, 5-10 years ago. :-(
 
Great country, very nice people
Click to expand...

Thanks, neighbor. My oldest son is living in Germany (Tübingen, close to Stuttgart) and we visit him once in a while (but not too often, since it's a 6 or 7-hour drive). I've visited Bochum a few years ago, to the mining museum.

But became a bit expensive in the last few years.
Click to expand...

Yes, indeed, inflation and shortage on the house markets are the main reasons. Recreational houses are used for living permanently, legal and illegal, so prices went up quickly.
 
Hi,

Partial measurement today, tomorrow I measure the rest (ex K0 and in & ex K1). For your engine number 1025820, you need intake valve 14711283010 and exhaust valve 14721283020, both used from engine serial number 1011936 until end of production, your info is correct (if the head belongs to that crankcase).

Found a set of NOS intake valves, tomorrow I will grab the exhaust valves and measure them, and compare the valves with a head within the serial number range of your bike and the K1 in & ex.

IMG-20250531-WA0007.jpg

As you can see, I paid 7 euros for 10 pieces, and packed them per set, but that 25 years ago.

IMG-20250531-WA0004.jpg

Valve disk is 38 mm, length is 100 mm. So it seems that your intake valves are correct for your head.
 
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Thanks a lot!
Yes, I'm pretty sure, that the head belongs to the rest.

Great, that the Intake fit.
Fingers crossed that I also have the right exhaust valves.
 
7€ per valve sounds fair. 😃
Click to expand...

I paid 7 euros for 10, 70 cts per valve ;) Exhaust valves were more expensive, as usual.

Would you please also check, if there are other differences? Maybe at the top end slot or the bowl in the disc?
Click to expand...

Yes, I will check, compare, and place some pictures in the thread "https://vintagehondatwins.com/forum...inquiry-into-differences-and-similarities.35/". This thread dives into all kinds of differences between the K0, K1 andK2. It's an ongoing thread, some sort of reference. Unfortunately, it takes more time than I have at the moment.
 
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jensen said:
Hmm, I dove into it and new measurements showing me wrong, the intake valve shown in this thread seems to be from a CB450 K1 and not K0. I bought these valves in piles, some bags were open, some had a p/n and some not. I think the valve shown as 14711283010 is actually for a K1. In the thread "https://vintagehondatwins.com/forum...inquiry-into-differences-and-similarities.35/" I will go into details.
Click to expand...
Thank you very much.

I ran through that post, very good, didn't find it yet.
Just for information, I have a K0 rear wheel, and noticed, the sprocket is 5mm more near to the center than at my K2 wheel.

Do you have two rocker arms for sale?
Today I disassembled my head.
Two are well but two are worn (exhaust)

And I need valve sealing rings.

Best regards,
Thilo
 
A thorough research costs time, I don't want to rush things and make a mistake (again). Writing up things cost even more time. I can only sit in a chair for 30 minutes, since I have a vertebra fracture, and I'm in my fourth week.
 
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jensen said:
A thorough research costs time, I don't want to rush things and make a mistake (again). Writing up thinks cost even more time. I can only sit in a chair for 30 minutes, since I have a vertebra fracture, and I'm in my fourth week.
Click to expand...
No, you misunderstood, I meant I didn't find your post of comparison, so the hole threat yet!
I didn't mean that I didn't find the valve post yet.
No hurry, get well soon!!
Sorry for my bad English.
 
jensen said:
Could you measure the valve disk diameter and length to compare with mine ?, please document in the other thread.
Click to expand...
Thank you very much for asking, yes, it's a pleasure to me.

I just disassembled an middle-early K1 (Last with M6 exhaust studs) and a K2.
I will make a sketch tomorrow and put it to your thread.
With engine numbers.
 
@jensen I'm posting this here, because it's not that high quality information.
But I'll spend more time on that and write a report in your theme.

I just put in all the part I have I'm my 1025820 head:
K later retainers, wedges and bushes
K later valves 33/38
K later camshafts

The inlet valves are looking wrong, they don't fit well, and because of this they sit not deep enough, not possible to adjust the valve gap.

But exhausted should fit!

1000083507.jpg

Next step is to take the dimensions of all valves and valve sealing ring areas (don't know the name, the contact surface of valve and head).
 
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