Topic: I think this is a new brake question!!!!!

[Quail "Owner of the comfortable k8"]

OK I did my homework and looked at the FAQ and old greenspun and did not find an answer.  You see you all have those 69-76 cb750's and those of us with the redheaded stepchild cb750k8's grovel on the floor just hoping to get tibits and scraps. 

 The new question:

I found out my bike was converted to a pre 77-78 master cylinder.  I found a good 78 master cylinder and bought the kit for it.  The M/C had no parts just the housing.  Who has a diagram of the 77-78 that you can see the parts to know where they go.  look at harry's picturefor a k0. Part #11 is not used in the 77-78.  But the spring on the 77-78 has a metal cap on it where the pre-77 M/C has part #11 (check valve).  I need to know which way the spring goes in the bore, cap first or cap inside of the part #16 which is pushed by the spool.

Or I could have just asked:  Which way does the spring go into the m/c of a 78k? 

[TwoTired]

Part 16 should be bell shaped, and the spring should fit in the bell where the clapper would go.  Don't allow the spring to interfere with the seal "lips".

[eldar]

I will check tonight. I have a 78k and I would not want the earlier models. I think the 78k is the pinacle of the sohc along with the 78f. I have the manual on disk and will try to find it tonight.

[Quail "Owner of the comfortable k8"]

Part 16 should be bell shaped, and the spring should fit in the bell where the clapper would go. Don't allow the spring to interfere with the seal "lips".

The spring is tapered just like the pre-77-78 and it will fit into the rubber seal either way, capped end or open end.  The cap is on the small end.

[TwoTired]

Part 16 should be bell shaped, and the spring should fit in the bell where the clapper would go. Don't allow the spring to interfere with the seal "lips".

The spring is tapered just like the pre-77-78 and it will fit into the rubber seal either way, capped end or open end.  The cap is on the small end.

I believe the cap should go into the rubber seal.  Drop the spring into the master body.  If the cap would block the pressure outlet then that's the wrong way. I'm pretty sure wide end should go in the master bore first.  Pity my fiche copy is too fuzzy to verify.  But, it sure looks like a bigger fuzzy at the master end of the spring.
Cheers,

[Quail "Owner of the comfortable k8"]

TwoTired  I think you will be right.  The capped end of the spring fits the outlet side of the M/C almost to well.

I wonder why they did not use the check valve after 77?  All the parts at the same for the pre-77 except the spool is a little diff and the one seal that goes on the spool is a little longer, and of course no check valve.

[Quail "Owner of the comfortable k8"]

well the answer is.....  Thank you ELDAR and I want to thank all of you that have been there when I needed you.

[eldar]

No problem. Finding parts and diagrams for our bikes can make an insane person look at us like we are off our rockers.

[Bob Wessner]

Sometimes I feel like an amateur archeologist. 

[Quail "Owner of the comfortable k8"]

this photo should go in the FAQ.  With the note that the push rod and adjusting nut are not on the k models.  And the dust boot is just a top hat design because of it.  It would be nice to have the pre-77 diag also.

[Terry in Australia]

Did you get a pic of an actual CB750K8 front master cylinder Terry? I've got the factory manual on CD and can print off the pic, then scan it and email it to you if you like? That rear MC in the pic might confuse someone looking for the correct part for his bike?

Red haired step child? You're spot on mate, the K7/K8 was like that hefty chick that your sister wanted you to go out with, you know, the one with the "great personality", ha ha! Cheers, Terry.

[Quail "Owner of the comfortable k8"]

Yes I did.  Do you have a clear diagram of the master cly of a pre-77.   I will photo chop both together and they can put it in the FAQ for brakes.