Author Topic: 1977 Cb550k - tappet hits cover (Read 9238 times)

Can550 · « **on:** August 05, 2017, 06:37:26 AM »

Hi

On my 1977 cb550k Cylinder #1 intake tappet gets adjusted to specs at a point where the screw goes down flat with locknut. It also feels that it sits higher than rest of tappets. I also saw some gouging inside the tappet/ valve cover which is hit by locknut.

When tightening the cover, threaded part of the cover hits the rocker.

I will be replacing O rings on these covers to increase clearance but would like to know what is the cause for this.

Found several posts by searching the forum but all were 1974-76 and recommending to change the cylinder head cover to improved one from 1977-78. In my case it is later model ?

Appreciate thoughts and advice

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uksparky · « **Reply #1 on:** August 05, 2017, 06:46:58 AM »

You should have the staked lock pins in your rocker shafts, if the thread of the tappet meets the nut your tappet is worn pretty good where it meets the cam lobe...pull the cover and inspect the tappet and shaft..punch out the lock pins

BomberMann650 · « **Reply #2 on:** August 05, 2017, 07:26:40 AM »

What sparky said.
Unless you made the adjustment with the engine on the wrong stroke

TwoTired · « **Reply #3 on:** August 05, 2017, 07:57:49 AM »

How do you know your bike has the later cover?
Early and late covers are interchangable.

Can550 · « **Reply #4 on:** August 05, 2017, 11:36:59 AM »

Quote from: TwoTired on August 05, 2017, 07:57:49 AM

How do you know your bike has the later cover?
Early and late covers are interchangable.

Because it has four bolts under breather cover holding pins/ rods.

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Can550 · « **Reply #5 on:** August 05, 2017, 12:11:57 PM »

Quote from: uksparky on August 05, 2017, 06:46:58 AM

You should have the staked lock pins in your rocker shafts, if the thread of the tappet meets the nut your tappet is worn pretty good where it meets the cam lobe...pull the cover and inspect the tappet and shaft..punch out the lock pins

I'll check the tappet but it seems length of tappet is fine it's the gap between tappet and valve that is too much

Got this bike few days ago. Not sure who and how adjusted tappets before.

Here's the shot

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TwoTired · « **Reply #6 on:** August 05, 2017, 03:18:42 PM »

I think you'll need to take off the cylinder cover to find out why the geometry is so wrong.

Can550 · « **Reply #7 on:** August 05, 2017, 03:23:49 PM »

Thanks TwoTired
I was hoping to avoid it but I guess can't so shall get on to doing so.

By the way I can't seem to find 1977/78 repair manual online. Stuck with routing of drain tube that runs from tank to seat area and routing of cables. Any direction

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uksparky · « **Reply #8 on:** August 05, 2017, 04:34:22 PM »

New valve seat in head, cut to deep when or if it was replaced or the tappet shaft is worn any side movement rocking back and forth also it could have the wrong tappet adjuster...tank vent hose comes down behind carbs, there it has a connector then goes down behind engine to the bike centre stand..cables go down frame under tank

Can550 · « **Reply #9 on:** August 05, 2017, 09:26:09 PM »

Quote from: uksparky on August 05, 2017, 04:34:22 PM

New valve seat in head, cut to deep when or if it was replaced or the tappet shaft is worn any side movement rocking back and forth also it could have the wrong tappet adjuster...tank vent hose comes down behind carbs, there it has a connector then goes down behind engine to the bike centre stand..cables go down frame under tank

Thanks sparky for info and photo. A little curious is it your bike?

I see breather tube is connected in different spot than mine. Mine is connected to airbox.

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uksparky · « **Reply #10 on:** August 05, 2017, 11:00:20 PM »

crankcase vapor hose from top of head goes to bottom of air filter..it shows in picture ...i have a 78 550k

TwoTired · « **Reply #11 on:** August 06, 2017, 12:45:53 AM »

Actually, not the bottom, but on the side near the bottom of the filter box.

Cheers,

Bankerdanny · « **Reply #12 on:** August 06, 2017, 07:14:42 AM »

The cover is easy to get off. Order fresh gaskets unless you know that the one on your bike is pretty recent.

Can550 · « **Reply #13 on:** August 07, 2017, 07:40:07 PM »

Don't know how the gasket state is. I have bike for only few days. That's part of hesitation to remove cover. I can see tiny bits of some glue drips which looks like that previously when worked on, gasket wasn't replaced.

It's not available locally here and will have to order from US.

is there any other liquid/ bond instead of gasket recommended?

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eigenvector · « **Reply #14 on:** August 07, 2017, 07:50:17 PM »

Valve cover gasket? Not that I know of - it's rubber/viton. You'd have to be pretty ham-fisted to mess it up.

I've never actually replaced mine and it doesn't leak.

I've seen what you're showing in that pic before - usually it's because I've adjusted the valves at the wrong crank position. it's easier to do than you'd think - get it wrong that is, and the service manual isn't that clear.

TwoTired · « **Reply #15 on:** August 07, 2017, 07:53:25 PM »

I don't know where "local" is for you. But, get a new gasket, where you can. Especially if its already been buggared.
Gasket goop is a good way to destroy your engine,as the oiling orifices are tiny. And, once blocked, metal destruction follows. Gasket goop breaks off and enters the oil distribution.

Cheers,

P.s. Glue and bailing wire "fixes" are not recommended for long servce life.

Can550 · « **Reply #16 on:** August 07, 2017, 08:04:05 PM »

Thanks TwoTired
Local is Toronto Canada. I see a bit of red bead even around oil pan.
Guess I will order both gaskets from 4into1. They have gasket of NE brand, any recommendation ?

I have checked with Honda dealer but no luck.

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TwoTired · « **Reply #17 on:** August 07, 2017, 08:14:21 PM »

I don't know about NE.
I've been using Vesrah.

Cheers,

Can550 · « **Reply #18 on:** August 08, 2017, 05:47:26 AM »

Pulled the cover off and

I'm surprised that all the screws and bolts were just snug and I didn't need any force to take them off yet there was no leak. There's a lot of gummy stuff around gasket area which I'll have to clean

Pictures speak thousand words.

My guess is tappets were adjust on wrong stroke which caused this damage. Any thoughts ?

Cylinders 1 and 2 intake rocker arms contact point with camshaft is no longer there except a tiny bit. I also see a pattern on cam lob. Two of the rockers have gone concave

I fortunately have few rocker arms sitting somewhere.

Would seek advice on how to determine good rocker arms and camshaft if can be reused with new rockers arms or this camshaft is gone ?
Thanks

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magnum56 · « **Reply #19 on:** August 08, 2017, 06:12:27 AM »

Yikes, with the rockers in that bad of shape, the cam is certainly toast as well.

Can550 · « **Reply #20 on:** August 08, 2017, 06:41:32 AM »

I have a decent camshaft sitting for sometime. It says R9 on it whereas the one in bike says R10
What could be the difference

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Can550 · « **Reply #21 on:** August 08, 2017, 06:42:26 AM »

Quote from: magnum56 on August 08, 2017, 06:12:27 AM

Yikes, with the rockers in that bad of shape, the cam is certainly toast as well.

What may have caused this ?
I see ample oil there equal amount all the way so couldn't have run dry

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Can550 · « **Reply #22 on:** August 08, 2017, 07:26:21 AM »

Further discovery
Found a bolt sitting rather stuck in #1 intake valve spring perhave making it harder to flex and broken piece of rocker arm sitting under spring of #1 exhaust valve spring

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TwoTired · « **Reply #23 on:** August 08, 2017, 08:18:05 AM »

The nut blocking valve spring compression likely caused the rapid wear on the cam and follower.
This is good reason to curse the P.O.

If you are happy with the oiling on both ends of cam, replace cam and affected rockers.

The casting numbers are to determine which mold the raw casting came from. If there is trend data for machining operations showing a consistent problem, they can then retire or repair the proper mold.

Be very careful installing the cover, so as not to bend valves. Many use rubber bands to hold the rockers up with all the adjusters basked way out. There is a nice warning drawing in the shop manual, showing contact interference.

You are going to be much happier riding with this motor after this repair.

Cheers,

Can550 · « **Reply #24 on:** August 08, 2017, 08:50:12 AM »

Thanks TwoTired
I have replaced camshaft and sprocket on two 550s before with rubber band method. It's just the gasket that it my worry. If it leaks then I have to wait about 10 days to get one.

Moreover I have some spare rockers and a camshaft but not sure how to inspect or examine for good health.

If little pitting or makings on rockers, what difference it may make.
Thanks

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Author Topic: 1977 Cb550k - tappet hits cover (Read 9238 times)