Topic: Cyl#1 Inlet Rocker contacts Tappet Cover! Help!

[whoismattclark]

After a full tuneup and a new exhuast (contemporary can slipon from an Kawa Ninja 500), my CB550 was running good -- albeit in 2nd gear around the block, but the oil light came on.  I noticed oil on the fins around cyl#1.  After some investigating I found that the #1 inlet rocker is coming in contact with the tappet cover!  I'm amazed I couldn't hear this while idling.

So, does this surely point to a bent valve or something in the head, or is the rocker cover just worn out?  I have a spare rocker cover from the original engine, and I'll pull both and compare the two, but I'd love some advice and hand holding right about now.

After self-teaching and forum reading for a year, I think I (the mechanic) am ready for a top end rebuild, but I don't have a gasket set and no funds to get one (wife put all toy funds on hold until after taxes).  Anyway to do this all on the cheap?  I'm not too fond of this engine anyhow, the original is waiting rebuild in the trunk of my '83 Lincoln.  That's right, good for 5 dead mob hits, or one dead CB engine.

thanks
MattClark

[TwoTired]

Cam cover rocker shaft wear.  Replace the cam cover.  Also check all cam follower faces and the cam lobes for irregular wear.  No need to pull the head to fix this.

I've posted about this before.  Maybe I should write up a FAQ submission.  Honda fixed this problem midyear in 76 with a design change.  If your other cover is also worn, shop for a 77 or 78 cam cover.

When you put the cam cover back on, loosen (almost remove) the tappet adjusters or risk bending lots of the valves.
If you use a cam cover from an earlier model, put o rings against the shafts in the tunnels where the cam cover end caps go to prevent the shafts from turning.

Good luck!

[whoismattclark]

The spare cam cover is from a 77, so I think it'll do the trick.  Thanks again, TT.

Don't know the history of the engine currently in the bike (not the original), could be an earlier model.  Anyway to tell year from VIN?  CB550E-1037xxx

So, what exactly happens to the cam cover after wear?  Does the rocker arm actually bend?  I'll search for your other posts if you don't want to rehash it all...


thanks again,
MDC

[SteveD CB500F]

OK TT.

Write it up for a FAQ and I'll post it for you.  Save all that typing in the future.

Steve

[whoismattclark]

update:  pulled both cam covers...no discernable difference under preliminary visual inspection...got no other ideas, so I'm giving the replacement a good cleaning, then bolting it on....

MDC

[TwoTired]

Anyway to tell year from VIN?  CB550E-1037xxx

1975 K1

So, what exactly happens to the cam cover after wear? 

The steel shafts rotate in the bores and wear away the soft aluminum of the cover  The rocker shafts migrate to the top of the cover.  The adjusters can compensate for drift until the rockers hit the adjustment covers.

Does the rocker arm actually bend? 

No. But, each rocker has it's own shaft and one end of the cam cover pivot point often wears faster than the other.  This Kant's the shaft and ruins the geometry so the cam followers are no longer flat across the cam lobes.  This can greatly increase the wear on both the rocker shaft cam followers AND the cam itself.

Were I in your position, I would keep the Cam, Cam followers/rockers and cam cover together as an assembly.  These parts wear in together and last the longest if not missmatched.  If you swap these parts from your 77 engine, swap them all together and keep their mated surface relationship.

Good luck!