Topic: "Fried Intake Valves" 1976 CB550

[Can550]

Hi,
Very new to this forum and CBs. Would like to know when someone says "intake valves are cooked" what does it mean in terms of difficulty level to repair/ fix this problem?
Thanks,

[BomberMann650]

The valve stem seal may have burned out and is leaking oil from the top into the combustion chamber.

Or the valve itself is damaged in its seat.

Either way, gonna need a top end rebuild, with special attention to the valves.

[Can550]

The valve stem seal may have burned out and is leaking oil from the top into the combustion chamber.

Or the valve itself is damaged in its seat.

Either way, gonna need a top end rebuild, with special attention to the valves.

Many thanks for replying Bomberman.


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[scottly]

Hi,
Very new to this forum and CBs. Would like to know when someone says "intake valves are cooked" what does it mean in terms of difficulty level to repair/ fix this problem?
Thanks,

Why did someone tell you the intake valves are cooked?? Exhaust valves are more likely to be burned than intakes. I wouldn't put any faith in such an off-hand diagnosis.

[madmtnmotors]

Hi,
Very new to this forum and CBs. Would like to know when someone says "intake valves are cooked" what does it mean in terms of difficulty level to repair/ fix this problem?
Thanks,

Why did someone tell you the intake valves are cooked?? Exhaust valves are more likely to be burned than intakes. I wouldn't put any faith in such an off-hand diagnosis.

+1

How do you even diagnose intake valve condition without disassembly and a visual inspection?

What problems are you having?

[b52bombardier1]

Have you checked your engine for compression?  Does it smoke?

Rick

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[Can550]

Thanks everyone
I don't have bike as yet. This question was asked as I got it from someone.


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[Can550]

As stated by the owner, "valve adjustment/ service was overdue and I rode bike past 500 miles, towards the end of ride bike made high pitch noise/ sound, engine lost power and stopped".

Bike has been garaged since then (which was probably over two decades ago).


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[BomberMann650]

That might have been the sound of it sinking a valve into the head.

[scottly]

" towards the end of ride bike made high pitch noise/ sound, engine lost power and stopped".

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The high pitch sound may have been the camshaft seizing in it's bearings from a lack of oil. If this is the case, the cylinder head, the camshaft, and the cam cover may need to be replaced.

[Can550]

Thanks
So now after many years of storage, is it ok to attempt starting it since engine rolls with kickstart?


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[scottly]

If the engine turns freely with the kickstart, then, yes, I would attempt to start it. You may want to put a small amount of oil into the spark plug holes first, due to the long slumber. Once you get it started, make sure oil is getting pumped up to the camshaft, looking through the tappet cover openings. The previous owner's recollection of what happened so long ago is suspect.

[Can550]

Many thanks Scottly
An attempt to start shall be made soon and I shall update accordingly.



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[ekpent]

 At least change the oil and filter if not done already first and look for metal and a peek at the spark plugs may show some clues also if broken metal from a valve or something is in a chamber. The old oil pan drop tells a lot also. If a cam bearing is already toast starting it again won't kill it much more.

[DaveBarbier]

Might want to pour some oil in the tappet covers to be sure there's lubrication for the cam on initial startup.

[flybox1]

" towards the end of ride bike made high pitch noise/ sound, engine lost power and stopped".

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The high pitch sound may have been the camshaft seizing in it's bearings from a lack of oil. If this is the case, the cylinder head, the camshaft, and the cam cover may need to be replaced.

Might want to pour some oil in the tappet covers to be sure there's lubrication for the cam on initial startup.

At least change the oil and filter if not done already first and look for metal and a peek at the spark plugs may show some clues also if broken metal from a valve or something is in a chamber. The old oil pan drop tells a lot also. If a cam bearing is already toast starting it again won't kill it much more.

These ^^^
A $14 USB borescope comes in real handy here 
If you get the bike, it better be cheap. Like well under $500 cheap, as you could be in for a time and money consuming rebuild.

[Can550]

Damn
It's much more than that


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[flybox1]

How much more....and does it have a title?

[BomberMann650]

Damn
It's much more than that

Did the advert have words like;
Café
Rare
Custom
Collectible
Antique
Vintage

Those are the four words people use to sell their broke down CB's at "there's a sucker" prices.

[flybox1]

Summer is coming, and riding season for us in N America.
If you want to ride...this may not be the bike for you.  Maybe you want to have a project bike for the summer?  I dunno....
Give us more details on what your in for, and show us the bike youre looking at. 
No one will snake it out from under you.  We're not like that in here.

In my area.  Just for comparison.  Short work would make this a rider.
https://seattle.craigslist.org/kit/mcy/6053891983.html

[Can550]

Hi flybox
My reason to buy this bike was just some good old memories from childhood.
No there were no such words in the ad.
I'm not looking at this bike for riding this summer. I have a road King for my riding.
I'm not worried about anyone taking away this bike. Not only because I have already bought it (awaiting transportation) but also that you all are bunch of good helping guys out here.

I did post a brief of this bike but by mistake posted under new member introduction. Will cut and paste here or rewrite later in the evening.

Your response and input is highly appreciated
Cheers


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[DaveBarbier]

Damn
It's much more than that

Did the advert have words like;
1: Café
2: Rare
3: Custom
3 1/2: Collectible
3 3/4: Antique
4: Vintage

Those are the four words people use to sell their broke down CB's at "there's a sucker" prices.

I thought there were six words there but after labeling them I see that you're right, my bad

[flybox1]

Can....i checked out the post.  No side view of the bike or closeups of what youre potentially working with make it tough to suggest anything other than what Calj mentioned....3000mi maintenance items first....and then try n start it.
Once you get it, start a thread over on the Project shop pages....post lots of pictures so your questions can be answered in one place, and your progress followed.

Cheers.

[BomberMann650]

Damn
It's much more than that

Did the advert have words like;
1: Café
2: Rare
3: Custom
3 1/2: Collectible
3 3/4: Antique
4: Vintage

Those are the four words people use to sell their broke down CB's at "there's a sucker" prices.

I thought there were six words there but after labeling them I see that you're right, my bad

Lol oops 

[Can550]

Lol
My comment of "much more" is referred to your suggested price of well below 500$ and not the key words/ luring words of seller


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