Topic: '76 cb550 oil in the exhaust.

[kerryb]

Trying to diagnose what might be letting oil into cyl #1 only.  The owner thinks it must be a failed valve stem seal.  I think it could be related to rings.  After startup, the engine slowly begins to smoke, then oil leaks from the drain hole in the #1 exhaust.  I suppose the first test would be compression and leakdown test.  Would a failed head gasket also be a likely culprit.  I may want to buy this bike,  so knowing what to fix first would be a plus.
Suggestions of test ideas welcome.
p.s. 10,000 original miles, all stock parts.

[denward17]

Whatever it is, just know that at least the head has to come off to inspect, to either replace valves/vavle guides, seals or whatever.

Once the head is off, you have to inspect cylinders/pistons/rings.

Oil in the cylinder is coming from rings or valve guides or valve guide seals or o-rings between head/cylinder.

[Stev-o]

  I think it could be related to rings. 

That is where I would put my money.

[calj737]

Smoking while running generally points to rings, but if the bike truly only has 10k miles on it, I’d find that hard to believe unless the motor has sat for a long time without operating and the rings are gummed up.

Oil dripping from the drain hole… are you dead certain it’s oil and not carbon/condensation?

A quick compression test of all 4 cylinders would be my first test. If #1 is truly down compared to the others, then it’s rings. If they’re all close to equal, it’s seals. It is possible to replace the intake seals without removing the head, but is better to pull the head and less hassle in the long run.fortunately a 550 head can be pulled with the motor in the frame.

[kerryb]

Thanks for the replies gentlemen,  I'll start a thread when the engine repair begins.

[seanbarney41]

Hold on now!  How long has the bike been sitting?  With low mileage low, the bike can't have been used for long or often.  Has the owner been lubeing cylinders for storage?  Are or were the rings stuck?  Is it really oil?  I have seen where it takes around 100 miles to get all that crap burnt out of the pipe.  If your engine is not broke, please don't fix it.  Everyone seems to think they can build a better engine than Honda did in the first place with a $25 cylinder hone, some rings, and a clymer manual.

[newday777]

Thanks for the replies gentlemen,  I'll start a thread when the engine repair begins.

Stuck rings is my guess with the minimal information given

Is this a bike that was sitting with gas left in it? How long?

[ekpent]

Hold on now!  How long has the bike been sitting?  With low mileage low, the bike can't have been used for long or often.  Has the owner been lubeing cylinders for storage?  Are or were the rings stuck?  Is it really oil?  I have seen where it takes around 100 miles to get all that crap burnt out of the pipe.  If your engine is not broke, please don't fix it.  Everyone seems to think they can build a better engine than Honda did in the first place with a $25 cylinder hone, some rings, and a clymer manual.

Agree on that and make sure that cylinder is not flooding out and its a mixture of gas and carbon deposits.  Is the smoke a heavy blue or more of a black color ?  White would be water condensation.

[kerryb]

Hold on now!  How long has the bike been sitting?  With low mileage low, the bike can't have been used for long or often.  Has the owner been lubeing cylinders for storage?  Are or were the rings stuck?  Is it really oil?  I have seen where it takes around 100 miles to get all that crap burnt out of the pipe.  If your engine is not broke, please don't fix it.  Everyone seems to think they can build a better engine than Honda did in the first place with a $25 cylinder hone, some rings, and a clymer manual.

Agree on that and make sure that cylinder is not flooding out and its a mixture of gas and carbon deposits.  Is the smoke a heavy blue or more of a black color ?  White would be water condensation.

I was thinking about stuck rings , while we are brainstorming this   it was sitting for awhile, smoke is more light blue than black
I don't want to pull it apart, so I'll try everything else first.  If a carb is overflowing to produce black smoke, then this could be cleared up with just carb work and run time.  That would be nice, but I need to be prepared for the worst!

[newday777]

Hold on now!  How long has the bike been sitting?  With low mileage low, the bike can't have been used for long or often.  Has the owner been lubeing cylinders for storage?  Are or were the rings stuck?  Is it really oil?  I have seen where it takes around 100 miles to get all that crap burnt out of the pipe.  If your engine is not broke, please don't fix it.  Everyone seems to think they can build a better engine than Honda did in the first place with a $25 cylinder hone, some rings, and a clymer manual.

Agree on that and make sure that cylinder is not flooding out and its a mixture of gas and carbon deposits.  Is the smoke a heavy blue or more of a black color ?  White would be water condensation.

I was thinking about stuck rings , while we are brainstorming this   it was sitting for awhile, smoke is more light blue than black
I don't want to pull it apart, so I'll try everything else first.  If a carb is overflowing to produce black smoke, then this could be cleared up with just carb work and run time.  That would be nice, but I need to be prepared for the worst!

Put a 50/50 mixture of acetone and Marvel Mystery Oil in the cylinders to help free up the rings, for a week, every day move the kick start a little bit to change positions of the rings and pistons(leave plugs loose in the head to release pressure as you kick it. At the end of the week pull the plugs, kill switch off, hit the starter to expell the mix, the run it easy outside as it'll smoke, then take a short 20 mile easy ride to work the rings free. Let it cool, then run another easy 20 miles. Report back. )

[kerryb]

Put a 50/50 mixture of acetone and Marvel Mystery Oil in the cylinders to help free up the rings, for a week, every day move the kick start a little bit to change positions of the rings and pistons(leave plugs loose in the head to release pressure as you kick it. At the end of the week pull the plugs, kill switch off, hit the starter to expell the mix, the run it easy outside as it'll smoke, then take a short 20 mile easy ride to work the rings free. Let it cool, then run another easy 20 miles. Report back.
[/quote]

That's a good idea, but before I can report back, I need to own it, register it, & get insurance, & go through the carbs (clear tube test).  So it will be a bit...

Thank you all for the head srart.