Topic: Head parts questions and pictures of Camshaft/Rockers

[sparkyman]

Still slowly making progress on my 78 750K, thanks to all of the help this forum has been so far.

I am going to take my head in to have it machined and the valves reseated etc as suggested on another thread. I am going to also have new valve guides installed while it's there. So part one of this thread is that I'm missing some pieces that I have either lost or were never there or I'm just going to replace. I would appreciate any suggestions on where to buy the following, considering I'm in Canada:

- Buying valve guides - I hear APE is a good place to get them.
- Oil Control Orifice - I seem to be missing one. Can't find them anywhere!
- Rubber seals under the cam trees - they are cheap, might as well get new ones.
- O-rings - Not sure what I need here? new ones similar to Oil control orifice rings?
- Seals around the Studs - no idea where to get these either.
- Dowels - Previous owner lost almost all of these!
- Rubber fin inserts - are these needed?

Think that covers that part.....

Next up, does my cam and rockers look ok? Cam lift all seems to be in spec based on Mark's book, from one side to the other. These may be slightly off as I'm new to getting these measurements accurately:

7.86 - 7.23 - 7.33 - 7.67 - 7.74 - 7.41 - 7.26 - 8.04







Inside:



Oustide:



Rocker Pin:



It's funny, I thought I was buying a pretty unmolested bike, but someone really made a mess of this. But I always say that if nothing ever goes wrong, then you never learn anything!

[City Boy]

Everything you have pictured looks fine to me.The rocker arms especially look good.Most have some flaking of the rubbing surface with age.

[sparkyman]

Thanks, that's great news since I have no experience looking at these things.

now I just need to know where to find some of the little parts I'm missing

[flybox1]

- Buying valve guides - I hear APE is a good place to get them. Yes
- Oil Control Orifice - I seem to be missing one. Can't find them anywhere!  Find a new head...or someone with a spare.  Post in Parts wanted pages, too
- Rubber seals under the cam trees - they are cheap, might as well get new ones.  HONDA brand if possible, but certainly best if there is .014" of compressible material.. and seal them.
- O-rings - Not sure what I need here? new ones similar to Oil control orifice rings?  Oil 'kits' have them all.
- Seals around the Studs - no idea where to get these either.  Fiche will list the size, and then order VITON from www.theoringstore.com
- Dowels - Previous owner lost almost all of these!  bummer..
- Rubber fin inserts - are these needed? no, but they do reduce vibration..

[flybox1]

Might want to buy this first.  Hondaman's Book.  Hondaman is a member here...

https://www.amazon.com/CB750-book-Putting-Them-Back/dp/0557310237

[sparkyman]

Thanks, I have the book and used it to find the lift and specs for the camshaft, I'm just looking for confirmation that I'm doing things right.

And of course some of these little pieces are tough to track down.

[PeWe]

Buy Oil orifice here (later model): http://www.yamiya750.com/index.php?main_page=product_info&products_id=3387
I have seen some on eBay too.

[754]

 That one rocker shaft looks a bit iffy   check the rocker, shaft may polish out.
The one cam bearing has a bit if wear, it may have not been  getting full oiling.
 The line on the rocker pad looks bad, check if its worn there with your fingernail. Often  it's just stain from where it stopped for a while.

 Where in Canada,  might have some parts.

[Jerry Rxman Griffin aka MuthaF'er]

You might consider a new cam. Within specs, perhaps but you have variation between cylinders.  A light performance cam will wake it up some too.

[sparkyman]

I'm in Winnipeg. None of the parts where there are lines feel like grooves, just lines.

[sparkyman]

You might consider a new cam. Within specs, perhaps but you have variation between cylinders.  A light performance cam will wake it up some too.

I've read here that sometimes it's better to let the parts wear in together rather than introduce a new part into the system. What are the thoughts on that?

I'm not against one way or the other.

[Jerry Rxman Griffin aka MuthaF'er]

You might consider a new cam. Within specs, perhaps but you have variation between cylinders.  A light performance cam will wake it up some too.

I've read here that sometimes it's better to let the parts wear in together rather than introduce a new part into the system. What are the thoughts on that?

I'm not against one way or the other.

Understand that but you will have valves opening to different heights in different cylinders was my thought. Better performance with all the valves opening the same plus increased performance with a slightly hotter cam too. It will continuing to work as is though. We tend to preach towards perfection 

[754]

Let me know which dowels.
 If cam is within specs it will be fine..

[sparkyman]

You might consider a new cam. Within specs, perhaps but you have variation between cylinders.  A light performance cam will wake it up some too.

I've read here that sometimes it's better to let the parts wear in together rather than introduce a new part into the system. What are the thoughts on that?

I'm not against one way or the other.

Understand that but you will have valves opening to different heights in different cylinders was my thought. Better performance with all the valves opening the same plus increased performance with a slightly hotter cam too. It will continuing to work as is though. We tend to preach towards perfection 

I appreciate preaching towards perfection. I think if I can go with this cam, I will though. I'd like to keep moving on this, and next winter maybe I'll do it all over again, with an eye towards more performance.