Topic: Rebuilding the head

[DxA_inc]

Let me preface this post with the fact that I'm new to the forum and rebuilding bikes. With that said, I bought a '75 CB750 engine seemed to run pretty good so I focused on other areas of the rebuild.  Unfortunately the camshaft snapped, I've taken the top end to a machine shop, but I need some wisdom regarding the new cam.  I can find used ones on ebay, but 40 year old cams make me nervous now. Are they safe, or is there some guidelines that I should follow in buying used. Should I just go with a new one, and what are the options.  Also the rocker arms look like they have some wear where they have been in contact with the cam, how do I find replacements for them as well? Thanks for the advice in advance.

[bollingball]

One name
http://forums.sohc4.net/index.php?topic=100474.0

[Xnavylfr]

Did the journals on the cam look burned???
If they were scorched colored then your top end wasn't getting oil properly and that is what snapped your cam!!! A good running engine/ well lubricated with proper oil flow can run FOREVER and not have to worry. A used cam or a NEW cam won't last long without oil!!!


Xnavylfr(CHUCK)

[DxA_inc]

Bollingball, thanks for lead, I've been searching the web looking for options, this opens up a whole new avenue.

xnavylfr, the mounting bracket for 1 &2 had snapped, I had supposed that that was the cause, it ground down the cam pretty good.  On the side of 3 & 4 every thing look well lubed.  is it possible for oil to get to one side but not the other?

[tool14]

yes ,check oil orfices for clogs

[70CB750]

Impressive damage you got there, good luck with the rebuild.

aftermarket cams:

http://www.cyclexchange.net/

http://www.dynoman.net/

Hondaman book:

http://forums.sohc4.net/index.php?topic=65293.0

http://www.lulu.com/us/en/shop/mark-paris/my-cb750-book-hardcover-edition/hardcover/product-16107855.html

explains how and what to check on a used camshaft and when to replace.  You can post in:

http://forums.sohc4.net/index.php?board=45.0

and ask for used camshaft in good shape, I am sure somebody here will have one.