Topic: Valve stem seal replacement FAQ

[Duanob]

1976 CB550K

I did my research and figure it can be done but is there an FAQ or 'How to' for replacing valve stem seals without taking the head off? My #3 cylinder is smoking like an old hag at idle but not much when cruising. I thought it might go away after putting a few miles on her but not yet. All other rubber on this bike has needed replacing so I figure the seals are shot as well. The bike runs great except for the smoking so for now I see no reason to pull the the head unless I really have to.

What tools do I need? I know there is some trick to installing the valve cover and not ruining/ bending my valve stems as well. any other tricks and tips? Thanks.

[TwoTired]

You don't have to take off the head, or remove the cam.
I just did it to my 78, and took pictures.  I just haven't had the time for a write up yet.

Bring the piston up to TDC and then back off a little bit.  Feed about 12 inches of 1/8 inch curtain draw cord into the spark plug hole.
(See pic DSCN0106)  Then bring the piston up to smash the card against the valves.  I used the rear wheel and the trans in 5th to rotate the crank. I also wedged the rear tire when the piston is in position so there was no possibility of the piston moving down.
Cobble together a spring compressor, using the cam cover bolt holes as and anchor and a piece of conduit with a "mouth" cut out of it to access the valve keepers.  (See pic DSCN0108, DSCN0104, DSCN0105

Remove springs and stem seal, install new seal, springs and mash the spring back down to get the keepers in.  Do the intake valve seal on the same piston.  Then back off the rear wheel, moving the piston down so the draw cord can be removed.

The repeat the whole procedure for the next cylinder/valve set.

Cam cover/cylinder cover install cautions a procedures have been post numerous times elsewhere on this forum.

Cheers,

[Duanob]

Awesome TT! I knew somebody had top have done this before. So as far as the rocker arms, they come off without removing the cam? That is great news. I was worried about having to remove the cam, chain, etc, etc. then reinstall. I think this should go in the FAQ section. It is a lot of help.

[TwoTired]

The rockers are in the cam cover/cylinder cover.  Taking that off is easy if you don't bugger up the screw heads (use impact driver).
Putting it back on can bend valves if you don't do it right. (Covered in many threads.)

Cheers,

[Duanob]

Thanks TT! I think this will be a winter time project. I've heard of some concerns with the rubber pucks inside the cover. Were you able to reuse yours our did you have to buy new ones?

[TwoTired]

Thanks TT! I think this will be a winter time project. I've heard of some concerns with the rubber pucks inside the cover. Were you able to reuse yours our did you have to buy new ones?

They were hard as granite and leaked.  Got new ones to put in there.  Gotta repaint the cover first, though.

Cheers,

[Duanob]

Thanks. They are cheap enough probably worth buying a set before I tear the cover off. TAS has a set for about $8. Anything else worth replacing once I get the valve cover off?

[TwoTired]

Kinda depends on how long the rubber bits have been there.Cam cover seal is just a big rubber o ring, the tappet covers all have rubber seals, and the rocker shaft end plug orings can also weep.

You should probably check for cam cover rocker shaft hole elongation, too.

There's the very top cover that has a rubber seal, too.  I use the thumbnail test on the rubber to see how supple it is, and if it has a chance of deformation which creates the seal when smoothed together.

Cheers,