Topic: '73 CB550K0 Top End Ticking

[fritzer_108]

Hello everyone,
I am reaching out regarding a new CB550 I just acquired. After readjusting the valves and checking the camchain, I found that a ticking noise in the top end has not gone away. Using a screwdriver, myself and a friend have narrowed it down to the right side top end as the rpm's change and the compression is fine on all four cylinders. The carburetors were also synced within the last year and the bike has 15,000 miles on it. Overall, I am just consulting the masses before tearing down the top end and inspecting or replacing everything and any help would be useful!
Vid 1:

Vid 2(Has Idling): https://youtube.com/shorts/FKnYAg62ngo?feature=share

[bryanj]

Check the exhaust to head gaskets

[fritzer_108]

Are those the copper rings or the half moon "clips" that hold the pipes? Which are you referring to?

[ekpent]

The copper rings are the crush gaskets.

[bryanj]

The half rings are not gaskets but spacers

[fritzer_108]

Gotcha, I checked all four and none have any issues with being squished or damaged at all. Would any of you consider a rocker arm or rocker shaft issue? It was sitting for about a year indoors.

[Scott S]

 The shafts that hold the rocker arms are known to wallow out the hole in the rocker cover. They'll tick even when the valves are in adjustment.
 The later '77-78 550 covers had pinned shafts to stop them from moving.
 It won't really hurt anything, just sounds annoying.

[Scott S]

 Just watched the videos; yours seems too loud to be the rocker shaft, maybe. Try pulling off just the rocker cover and seeing if the shaft has excessive play.

[HondaMan]

I had a high-mileage 500 for a while in 1973, and it ticked loudly, too. I put in some 20w50 oil after I tuned it up, and the noise went away! Then I found out the previous owner was using 10w30 oil in it, for the 2 years he owned it.

[fritzer_108]

I think I may have found it. The rocker arm on the side of the noise has a huge dent and crease on it! Maybe that's what did it?

[dazemc]

Is this the year they fixed the rocker arm shafts? I had a shaft fly out the side of my old motor and it had a similar dent on the rocker. Look to see if the holes that the rocker arm shaft sit in have an oval appearance or play to them. 

[Little_Phil]

Pinned shafts didn't come in until later. (75-76?). Sounds awful top and bottom.
Always used 10W-40 year round. Never tried 20W-50 as at the time it was for extreme high temps which excludes temperate UK. Having said that traffic and stop lights may mean that bikes are subject to longer periods with poor cooling, so may try 20W-50 in summer.

[seanbarney41]

I think I may have found it. The rocker arm on the side of the noise has a huge dent and crease on it! Maybe that's what did it?

umm dude, that is serious engine wear.  It might run for a little while longer before something catastrophic happens.

[MRieck]

I think I may have found it. The rocker arm on the side of the noise has a huge dent and crease on it! Maybe that's what did it?

umm dude, that is serious engine wear.  It might run for a little while longer before something catastrophic happens.

I agree. Rocker arm pad wear like that indicates oil starvation. That cam lobe is shot too.

[Scott S]

 And all that missing material is inside the engine somewhere.

[craz1]

I recently went thru this with my 74 CB550. I decided to put the later cam cover with the pinned shafts because my original shaft holes were wallowed out. I also had my cam and rockers hard welded and reground. If you'r going to tear into the top end might as well look at your bores also. Do it right and you will not be sorry

[wolf550]

Keep an eye on eBay the last rocker cover I saw on there with the pinned shafts went for 50 plus 16 shipping.

[fritzer_108]

Would I just transplant the existing shafts and rockers to the new pinned cover? Or would I also have to buy all new arms, shafts, and valve adjusters?

[TwoTired]

The rockers have a contact surface follower to the cam which is married for wear to the cam lobes.  If they are pristine, you can reuse the rockers and cam.  The covers with pinned shafts have 4 shafts instead of 8 and have extra length to allow for pinning them to stop rotation.  If you don't stop the shafts from rotating, you'll eventually get wear in the soft aluminum covers from the steel shafts rotating, instead of the rockers rotating on the steel shafts.  My theory is that good oil and frequent oils changes help extend the life of non-pinned shafts.  But, hardly anyone has perfect maintenance history on these old bikes.

IMO, the best "cure" is to get the late model cover used complete with the cam it's married to.  Assuming the cam bearings aren't also buggared with poor oil change history and/or using the wrong oil with low zinc content.

Cheers,

[fritzer_108]

Keep an eye on eBay the last rocker cover I saw on there with the pinned shafts went for 50 plus 16 shipping.

Where did you see that? I've been searching all day and can only find '71 or '73 rocker covers? I'll bite if I can find it!

[wolf550]

This was last month that it ended.
These covers don't usually go for that price
you can see on the top of the cover where the four bolts secure the rocker shafts.

 only one bid on it.

they are out there.

[fritzer_108]

This was last month that it ended.
These covers don't usually go for that price
you can see on the top of the cover where the four bolts secure the rocker shafts.

 only one bid on it.

they are out there.

Gotcha! Would a 1977 CB500 valve cover work then instead of a cb550 one? I've heard that they are similar but are they compatible at all? And what year did they implement the new shafts?

[bryanj]

All 500/550 will fit, only thre K3 model had the mod from the factory

[dave500]

500 and 550 even share the same head.

[craz1]

And they share(CB500) the same problems you have now. Get for the newer cover. They are hard to find.

[Scott S]

I think I may have found it. The rocker arm on the side of the noise has a huge dent and crease on it! Maybe that's what did it?

 What did that cam lobe look like?

[Little_Phil]

And they share(CB500) the same problems you have now. Get for the newer cover. They are hard to find.

There was a service kit issued at the time,  12300-390-305. But include only the rocker cover and the pinned rocker shafts. Picked up one a few years ago from DSS.

[fritzer_108]

Gotcha, well I did find a 1977 CB 500 head with the 4 shafts. It's on its way, and I do truly appreciate the help that you all gave! I'll be back if that's not the issue I suppose😅

[bryanj]

There was never a 77 500 in the US. There was a 500 K3 model in Europe but not many of them

[craz1]

Probably means 550

[Deltarider]

All 500/550 will fit, only thre K3 model had the mod from the factory

My CB500K2 (ED, F, G) aka K2 GENERAL EXPORT (CMSNL) had the mod. There's only one way to find out yours has: write down your serial engine number and consult that particular page (Camshaft - Valve) in the appropiate parts list.

[Remcod]

I managed to acquire one but after removing the nut the valve axel holder screw wont come loose. Is it supposed to just drop out? Or is it a screw?

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[TwoTired]

Not sure why you need to take it apart, but it’s a tapered body pin that wedges in place.  I gave up trying to get one out, as the rockers were good.  Possibly heat the aluminum alloy cover and stack some nuts to protect threads on the taper pin and whack it with nylon or brass hammer.

Wound be a shame if the whacks caused damage to the cover, though.

[Remcod]

Ok thanks, i was just curious if they would come out indeed to swap a tappet if need be, im gonna leave it as it is.

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