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Old 09-16-2009, 08:13 AM   #1
cb550newbie
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Hi all,

Sometimes when Im at a stoplight blue smoke will pour out of the exhaust. This only happens I'd say at 10% of the time, the rest no smoke.
I know blue means burning oil, but what could the problem be that it only happens a small fraction of the time?

oh and I have a 1975 CB550 Four, with only 4700 miles on the engine. And it really runs amazing other than the smoke.

Thanks again in advance for any information!
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Old 09-16-2009, 09:09 AM   #2
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Could be the valve stem seals are worn and when enough oil pools in the head it leaks into the cylinders. Also might be a problem with the oil control valves in the cylinderhead.

Anyhow that's my wild guess. To replace them you need to remove cylinderhead which means you need to remove the engine.
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Old 09-16-2009, 09:49 AM   #3
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Quote:
Originally Posted by seruzawa View Post
Could be the valve stem seals are worn and when enough oil pools in the head it leaks into the cylinders. Also might be a problem with the oil control valves in the cylinderhead.

Anyhow that's my wild guess. To replace them you need to remove cylinderhead which means you need to remove the engine.
It's a good guess; I was going to say valve stem seals too.
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Old 09-16-2009, 01:13 PM   #4
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Thanks for your responses!..

any ideas how much would something like that cost?
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Old 09-16-2009, 01:16 PM   #5
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"Anyhow that's my wild guess. To replace them you need to remove cylinderhead which means you need to remove the engine."

I thought you could get the heads off with the engine in? Never did it, but I thought they were designed like that.
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Old 09-16-2009, 01:34 PM   #6
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When I get blue smoke coming from my tailpipe my wife will ask me to go to the deck.
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Old 09-16-2009, 01:40 PM   #7
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Sounds about right, if it was water cooled I would say could be a head gasket and your steaming coolent but not the case here.
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Old 09-16-2009, 01:44 PM   #8
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IIRC you have to pull the engine on Honda's to get at the head. It's going to cost a lot if you go to a dealer. Over a grand. If you can find a dealer who will touch a biker that old. Many won't.

Or if you are mechanically inclined you can do it yourself. It's really hard, but you need tools and a manual.

I doubt that the bike is worth the cost of repair.
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Old 09-16-2009, 03:44 PM   #9
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It also may be a head gasket letting loose. Old Hondas are notorious for head gaskets getting ossified and leakning oil into a cylinder. Pull the plugs, the dark one will be the cylinder that's burning oil. You can remove the head with the motor being in the frame. Get a cam-chain cutter, and a master link from Honda, they still stock 'em. Buy a manual for the marks you use when lining up the cam/crank marks. It's not that hard.

While you're at it, go get the cylinder head re-worked, so you can blow the lower end up with all that new-found compression. Or just ride that old Honda 'till it makes a good coat-rack.
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Old 09-16-2009, 06:49 PM   #10
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Quote:
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It also may be a head gasket letting loose. Old Hondas are notorious for head gaskets getting ossified and leakning oil into a cylinder. Pull the plugs, the dark one will be the cylinder that's burning oil. You can remove the head with the motor being in the frame. Get a cam-chain cutter, and a master link from Honda, they still stock 'em. Buy a manual for the marks you use when lining up the cam/crank marks. It's not that hard.

While you're at it, go get the cylinder head re-worked, so you can blow the lower end up with all that new-found compression. Or just ride that old Honda 'till it makes a good coat-rack.
You can pull the 550s head in the frame? Cool. I thought that only Kawasakis allowed such ease of owner maintenance.
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