Topic: son of a gun

[mk0094@hotmail.com]

ok , so this weekend, i ripped the frame down to nothing on my cb750, painted it a fresh flat bolack and put some crappy clear over it that looks hazy and a little white, but still fine by me, it is almost ready to get together at this point......

then i polished the valve cover up, looks great. then i was checking the valve tapet clearance, and noticed that the 3&4 cyl. were not moving (Mother fudger!) the cam shaft broke benieth the first cap that holds it down on the 3&4 side of the engine before the first cam lobes.

my question is how do you break (and i mean it is a clean break, right don the shaft) a cam shaft? what a suprise for a day the was looking so promising. well, bought a new one off ebay for 18$ and now i have to figure out how to change it. it does not seem that hard, my buddy has the manual, so i will borrow it from him, but any extra tips are appresiated.

thanks
mike

[Lumbee]

...was this thing running when you got it?  A guy on the hondachop board said he had a cam shaft break, and he actually made it home on 2 cylinders.  Inspect the cam shaft, and if you have a decent dig. camera snap some pics of it, I'd like to see it.  Does it look like it was burned through...like it was due to friction?  Its possible maybe you had a clogged oil jet, and were not getting lubrication to that area.  Did it break right where the bearing cap clamps down on it?  Its also possible the bearing caps where over torqued (to tight), and this caused undue wear.

...like I said, some good detailed pics would be nice.

[bryanj]

If it broke you also got bent valves and the usual reason they break is if the journals sieze because of blocked metering jets under the cam covers, sorry to say it but you really need to pull at least the top half (head and block) and do a lot of careful cleaning with probably a new cam chain and rollers

[crazypj]

And you have to pull the motor out unless someone has removed the lower set of top tubes ( A drag racing trick I believe)

[Terry in Australia]

Hey Mike, forget the heart-ache of a top end rebuild, buy a complete running engine! Just pull up Ebay and type "Honda CB750 Engine" and you'll probably find one in your area. Here's a K0 engine for 49 bucks:

http://cgi.ebay.com/ebaymotors/KO-Honda-CB750-Engine-CB750E-1036834_W0QQitemZ4621427121QQcategoryZ35595QQrdZ1QQcmdZViewItem

Cheers, Terry.