Topic: Engine surgery -top end -CB750K4

[andy750]

Hi all,
Well this weekend I get to do a little top end surgery on my K4 (CB750) engine (now removed with cam cover off) to replace the rubber seals under the cam towers (that Terry and Whaleman pointed out to me on Sunday as the cause for the oil leak - ordered seals from WesternHills Honda on Monday and they arrived Wednesday!!). Now I read the workshop manual last night on how to remove the camshaft and what comes first etc etc.....first time doing this on my own so I was wondering if anyone who has done this before (successfully!) has any pointers on what I should be careful of or look out for....I know that I have to secure the cam chain so that it dosent fall into the engine and I have to rotate the engine to align the key marks at the end.....but anything else?? any good tech info appreciated!

Thanks in advance,
Andy in Boston

[WHALEMAN]

1. Mark the cam bearing top halfs so you can put back exactly as they were.
2. When you take the bolts out of the cam sprocket have the bottom sealed with rags and tape so it is impossible for a bolt to drop in.
3. The first time you try to take the cam out of the sprocket it will appear impossible. It is possible and you do not need to force anything.
4. When you bolt the cam towers back use a torque wrench as these can strip out.
5. There are two very small o-rings where the oil is pumped to the cam towers from the head. Do not loose these and make sure they look good also.
6. I always use a drop of locktite when I bolt the cam sprocket back on.
7. You might want to take a digital photo of the location of the crank and the end of the cam with the grooves so you can get the cam timed correctly.
8. Again, Make sure nothing can fall in because it will.
9. Yes, you need to tie a wire to the cam chain when you pull the cam out so it can not fall in.

[andy750]

Thanks Whaleman that was the kind of advice I was looking for. Much appreciated. Illl let you know how it all goes....
Cheers
Andy in Boston

[techy5025]

On the K0 at least, the intake side of the cam towers uses bolts
that well probably require a thin wall socket if you are going to
use a torque wrench to tighten them.  I took mine off with a
regular wrench because no socket I had would clear the cam
tower itself.  They go back on tomorrow so I will be chasing the
right socket.

They also have a phillips head but I can't imagine using it for
anything serious.

Jim

[HondaMan]

There are a couple of real long bolts that hold down these towers. On the K2-K4, many of the cylinders only had about 5 threads holding these down. Torque these long ones to only 7 in-lbs. Any more will damage those threads, requiring cylinder removal for rethreading.

[techy5025]

Why do the intake sides have these Phillips head bolts....look
like a regular six sided bolt with phillips in the center?

Jim

[andy750]

Thanks Hondaman thats great advice and just what I need to know.
Much appreciated
Andy in Boston