Topic: 1977 CB550k valve cover swap, different rocker arm shaft mounting

[jamesk]

Hey guys, I'm swapping the valve cover from my 77 cb550k because the old one is cracked. I got a used on and I noticed that the rocker arm shafts on the new one are loose, as in they can be pushed out easily. The old one has a slotted end on the shafts and the new ones just have a threaded hole. I was going to swap over the rocker arms and shafts to the new one but I'm not sure how they come out.

Two questions :

1. How do the slotted shafts come out? I tried to turn them with a large screw driver and they didn't budge.

2. The new cover seems to use a different shaft design. Is it supposed to be freely removable like this and does the side cover all that holds it in? 

See pics.

[jamesk]

I should also add that another difference between the two designs of valve cover is that the old valve cover has four studs under the breather cover (this is the one that has the slotted rocker arm shafts) and the new one does not have the studs sticking up through the breather cover (the rocker arm shafts in this cover slide right out). See pics, first pic is old damaged cover, second pick is new cover.

[BomberMann650]

77 was the year honda cured the 550's valve train curse.
Which is why it really sucks that your 77 cover cracked!  Honda changed a few things in the rockerbox - your rocker shafts will not fit a pre 77 cover as a result.  Because they are longer, and held in place by a press-fit-and-nutted pin.  Near the sprocket dome. 
Which answers your question - Take off the said nut, warm the area with a torch, then tap the pin out.  Use a bolt to help pull the shaft from the bore.
If you scooped up a pre-77 rockerbox with shafts that are close to falling out.  Chances are high that it's cursed too.

How badly did your cover crack anyway?  It would be worth repairing as that part is highly covered and honda did not have a long run of that part.

[jamesk]

It's pretty bad. I had my machinist that I use look at it and he said he'd charge over $200 to repair it because it would be such a pain in the ass. He said you would have to grind out the crack TIG weld it and build up the lip at The Mating surface where it's pushed down, then bake it in an oven over several hours to cool it down slow while you're paying attention to it the whole time. Then after that he would have had to use a tool to chase the rubber gasket Channel back out. After that I found a used one for about a hundred but I didn't realize it was different until I already got it. On the new one, the shaft do come out easy but they don't seem to have any play or slop. You think this would be a problem to use on my engine?

[jonda500]

You think this would be a problem to use on my engine?

Nope, no problems with using the earlier cover!
John

[DaveBarbier]

If the replacement cover doesn't have worn out rocker shaft bores then it'll work. Just replace the rockers and install them in the same location as they were in your bad cover.

But just know that Bomber is right and that it's an inferior design. The shafts spin and wear the bore and then your valve lash becomes inconsistent and eventually can lead to damage. Some people put an o-ring between the rocker shafts and the end cover to help keep them from twisting. If I were you I'd run it and keep a look out for changing valve lash and also watch eBay for a '77 - '78 cover.


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[jamesk]

Ok thanks for the info guys. I'll keep an eye out for another valve cover in the newer design. How crucial is it to swap the rocker arms over if the ones on the new cover look to be in an good of shape as the old ones on the old cover? Is ok to use the new cover arms a d all?

[BomberMann650]

I've swaped rockers out of necessity.  Cams too. No big deal.  Tho I'm sure the parts wear together over time and can be uniquely paired to each other.  So if one of the lobes has a lo/hi spot, the rocker paddle would start grinding that shape into a different lobe if changed.

The best way to damage a rocker/cam is to run a worn out rocker box or set the tolerances to tight.

[jamesk]

Ok thanks for info, bomber. I'm gonna get it back together tonight but it's gonna be a late one 

Got the rings swapped, cylinders honed, pistons reinstalled and valves lapped. Just got button her back up. Ready to get some riding  in tomorrow if all goes well!

[flatlander]

do put some o-rings between the rocker shaft ends and the endcap. that should keep them from turning and if your new cover is still good, prevent it from getting worn out. the same size o-ring as used on the endcap should do the trick.
if your cover is still good and you can keep it good this way, there's no need to search for another one with the pinned shafts.

[jamesk]

Will do. Gonna stick the old orings from the end caps in there. Good call!  Coming together. It's 2:3i but I think I'm gonna a keep going 

[DaveBarbier]

Since apparently your old rockers are in good shape I would swap them over and keep them matched. Not super critical, but otherwise they have to wear to match each other. Removing the rockers from the pinned shafts is easy, especially if the cover is now trash. Put the nut on the threads of the pinned shaft a couple twists to protect the threads, heat around the pin with propane, support right under the pins and whack with hammer.

Also, retorque the head after 24 hours.


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[jamesk]

Thanks for the tip. I'll see if I can get them out this morning. On the retorque, do you mean before I start it up , wait 24 then retorque or 24 hrs after it's been up to temp?

[TwoTired]

Something to be alert for--
When wear occurs in the old style cover, one side of the shaft bearing surface wears faster than the other.  This causes the rocker to cant, and focuses the cam to follower contact pressure to shift to a far end.  This creates abnormal wear on both the rocker cam follower AND the cam lobe.

The upshot is if your used rockers show any uneven wear on the rocker cam follower face, your existing cam lobe will now wear abnormally in that same pattern.

Please don't run a good cam along with a cover having canted geometry.
Even if you keep the rockers matched to the mated cam, the geometry alteration will abnormally wear both components.

The only way I would run a 77 550 cam and rockers with an unupdated cover is if the old style cover was brand new and unworn.  And then use the squished Oring to keep the rocker shafts from turning.  In fact, I have done just that, to preserve cam follower to cam contact wear surfaces.

Cheers,

[BomberMann650]

I've taken up the habit of running a right angled mechanics pick along the inside of the shaft bores.  If you feel a ridge (usually on the top side leaning away from the cam) then the shafts have started boring the bore.

Really bad examples of this wear can be seen with the naked eye and a flashlight.

[jamesk]

Thanks for the info guys. I didn't notice any abnormal wear on the new rockers and I ended up using the four orings from the end caps to sandwich in there. Timing was way off but now the bike is running sweet!  It's like 2 am and I was ying-yingin it in my garage once I got the carbs synced. I'm sure my neighbors appreciated it 

I may get a second opinion on repairing my old over and I'll keep my eye for one. If any one runs by one, I'm interested!

Here she is wanting her tank and seat put on!

[flatlander]

sounds encouraging. if your tappet clearance is off again, after a short time, then your replacement cover is most probably worn. keep an eye on that.

[RAFster122s]

James, I would like your old '77 cover and rocker shafts for the cover.  PM me what you would want for it to send it to me?  Zip code is 37617
Thanks!
David M

[jamesk]

I'm not looking to sell the old setup just yet, still haven't given up on repair. I'll let u know if i decide to let it go.

[RAFster122s]

Thanks James, saw you indicated you were going to get some other quotes. If you decided to abandon it, then let me know.  It is a labor intensive task.

David

[jamesk]

My girl is back in action and lookin good    Think I need to change the bearings on the front wheel soon tho 

[jamesk]

Hey Guys, I picked up another valve cover from a '77 with the updated design.  Although it's rocker arms don't show any detectable strange wear patterns or any visible differences from my original rockers, I'm willing to swap them over if I could get the damn things out.  I tried heating with a heat gun and hitting the pinch nuts with moderate blows but they shafts still don't budge (my only torch at the moment is map gas I was concerned to overheat things).  Any other tricks to get the new style rocker shafts out?

[DaveBarbier]

A hydraulic press will do it . I use propane, you should get a bottle anyway, good to have around. Heat up the surrounding aluminum and give it a sharp whack with a hammer. Just make sure you've got wood or something directly under the pin that you're removing so it's supported. And, when you reinstall, do not over tighten the nuts. It's easy to crack.


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