Topic: '78 CB550 valve guide seal replacement howto?

[jwalters]

Hello, from my previous posts, looks that I have some bad valve seals.  Unfortunately, the service manuals I have, don't cover replacement.  Is this because it is a major deal?  If not, does someone have a howto (or a few words of advice) that could walk me through the replacement?

We have the valves exposed.  I am not sure if I can remove the springs from the top, and  get at the seals this way or if I have to take the whole head off.  It appears that there are little clip rings of some sort on the valve springs, if I remove those will the spring come out and expose the valve guide and seal?

[Paul]

You need to remove the head first.
Actually...you need a manual first,
cam chain etc all have to come off.
Once the springs and clips are removed the valve will drop down (Not all the way whilst in situ - but too much to get the bits back on again. Unless you can train some bugs to get in there and hold them up.)
To get at the valve seals, you need to compress the springs first- to below the depth of the collets (retaining clips) in order to get these out.
there is a tool for this (Valve compressor) but careful improvisition may work - Caution...do not bend the valves.
The clips will slip from your grasp and you will loose one or two for a while.
Remove the Pair of springs from each valve and watch out for the two steel shim washers under each.
pull the valve seal up making #$%* of the little retaining spring also. (New seals come with new spring retainers)
Whilst the valves and head are off, you may want to take the oppertunity to check the valve sealing
you'll get there..  
Look into this site ...there are a few manuals here or at least directions on how to find them.

[dusterdude]

how about finding an adapter for an air line and finding a spring compressor that will fit from the top.

[jwalters]

Would that allow me to get at the valve seals from the top, without removing the head?

[dusterdude]

well im no expert on these heads,but you can use them on car engines,so what the heck it might work

[TwoTired]

I have removed valve springs and replaced stem seals on auto engines by using air pressure to hold the valves in place.
I have also used soft nylon rope fed into the spark plug hole and then rotating the crank to bring the piston and rope up to the valve and hold it in place.  Then compressing valve spring removing retainers. etc. etc. Pull out the rope when done.

Don't have to take off the head in either case.

I've not done that to the CB550 yet, though.
Cheers,

[lucky]

A am doing that right now and the problem is that the valve spring is surrounded by the aluminum head casting.

I used  a 1/4 rope in the spark plug hole to keep the valve from dropping down.
Worked ok. You have to stuff it down with needle nose pliers. Be careful around the spark plug threads. But the piston should be all the way up it the cylinder you are working on.
Once you push the valve spring down you can use a magnet to remove the keepers. Then slide the new seal on the valve stem.
The problem I am having is getting the spring pushed down and the keepers back on.

I am going to try a valve spring compressor that is made for small engines and looks sort of like a scissors or chopsticks to get at the valve spring. I will let you know how it all turns out. See my thread under PROJECTS>LUCKY

[dave500]

id pull the head,decoke it and lap the valves while i was at it,if they need replacing itll have burnt oil residue on the stems in the ports,check the guide wear,if they are sloppy itll only distort the new seals till they also leak,its only half a job otherwise.