Topic: Sill Smokin'....but still runs like a champ!

[whoismattclark]

In previous posts in the last two weeks, y'all have helped me diagnose issues with the rocker cover, dyna ignition, and oil sending unit, but this bike still ain't so road worthy.  1977 CB550f, pods, V&H exhaust...

She starts fine.  She runs super...strong powerband, reliable power.  However, she smokes like a chimmney after she's warm.  The smoke has always been present since I got her running a couple of weeks ago, but not so bad at idle and around the block, but I took my first longer trip, and the smoke gets pretty bad to very bad.

I've gone back and forth on whether it is white or blue or a mixture.  But the exhaust deposits are oily, not dry and sooty.  I bought a compression tester (about time...thanks to everyone at sohc4, I'm learning step by step), and did my first compression test.  Numbers were good (135, 140, 130, 135), and #2 cyclinder was the one I was most worried about!

I'm in LA, so plug chopping is not easy, plus, I've never done it before.  But I did try it at idle, and at 1/4 throttle.  #1 looked rich.  #2 looked a little oily to me (though perhaps i was projecting) and a little rich.  #3 and #4 looked good.

So, after good compression numbers I am officially stumped.  Help.  I'm running pod filters, with a Vance and Hines can.  Carb jetting to match pods.

[whoismattclark]

One thing I forgot to ask...before I started this motor for the first time, I put a tablespoon of oil in each cylinder....now, I might have not measured perfectly, and might have gone overboard.  But, that was many weeks ago...surely that oil would have burned off since then right?  I figured it would have burned off almost immediately.

[TwoTired]

You initial compression numbers appear okay.  However, the conditions for the test can be significant.

Was this an engine hot test?
Were both the throttle and choke fully open?

Did you follow up a dry test with a wet test?  (teaspoon of oil in each cylinder?)

The later can identify if the rings are sealing.

If they are, and the cylinder blows oil, then suspect valve guide wear or failed valve guide seals.

Is #2 firing?  Does the head pipe get hot?

Look at:

http://www.verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm

Do your plugs look oil fouled?   Or, if they have been used for a while ash fouled? Or, possibly ash deposits from burned oil?

Cheers,

[whoismattclark]

thanks TT, I thought you'd be first to respond....

...this post kinda picks up where http://www.sohc4.us/forums/index.php?topic=1486.0 left off, different poster similar problem....

I did not do a wet test (I thought the higher numbers ruled out rings or seals, but i'll do it anyhow).
The engine was hot.
Throttle and choke open.
Starter clutch is out -- test took many kicks.
All cyclnders are firing, and firing well.

I don't think the plugs were oil fouled or ash fouled.  The darkness on the plug looked much more like a rich condition.  The plugs are pretty new, but not brand spanking (since they suffered through all my timing/electrical troubleshooting thus far), so I might buy new plugs and to get a better read.

[TwoTired]

If there is no oil or oil deposits in the cylinders, but there are in the exhaust, then exhaust valve guides are suspect.

Something to think about:

If there is already oil inside the exhaust system from whatever source, it will burn off and smoke as the system heats up during use and as the system saturates with heat, such as after a longer ride.  If no more oil is pumped into the exhaust, is will eventually subside.
However, if there is a cylinder problem feeding oil into the chambers/exhaust, then the smoke volume won't subside.

Cheers,

[whoismattclark]

Wet test will have to wait until tomorrow.  But give me something to think about tonight....if you would:

Assuming Valve Guide wear:  After reading other posts, I'm quite intimidated by the prospect of finding valve guide replacements for a cb550.

Assuming the worst, Rings:  I have to sell the bike off.  No money for a big job like this.

Assuming the best of the worst, Valve Stem Seals:  These seals come in a top end rebuild kit, do they not?  I see the Versah kit at OBB is $70 or so. Plus, $30 for a torque wrench, which has yet to make its way into my tool collection.  Are these the only costs I would be looking at?  Because that's about all I can afford.  Though I've never done a top-end rebuild.  I think I'm ready to give it a go.

Aside: Even after I fix the smoking, I will probably have to sell the bike -- Uncle Sam took a startlingly big bite out of my pocketbook this year -- but as a matter of principle, and to recoup costs, I'd like to send the bike off to the next owner as a reliable daily driver.  Any advice here?

[Gordon]

  Any advice here?

Yeah, sell something else and keep the bike!

[whoismattclark]

Yeah, sell something else and keep the bike!

I like it, true blue SOHC fan!  Don't worry...I still have another 550 waiting to fire up and get back on the road...seems there's no short supply of project 550's, at least in SoCal.  Now I understand why my sister takes in stray cats, spends a lot of money on shots and vet bills, then gives them away....   

[TwoTired]

Assuming Valve Guide wear:  After reading other posts, I'm quite intimidated by the prospect of finding valve guide replacements for a cb550.

Probably better to find a low mileage head replacement.  Ebay and patience?

Assuming the best of the worst, Valve Stem Seals:  These seals come in a top end rebuild kit, do they not? 

They should.  Check with the seller first.

I see the Versah kit at OBB is $70 or so. Plus, $30 for a torque wrench, which has yet to make its way into my tool collection.  Are these the only costs I would be looking at? 

Valve spring compressor.  The seals live under the valve springs.

  Any advice here?

Make decisions based on knowns rather than speculation.
Planning ahead can be a fun excercise.  But, is there a requirement for a snap decision at a latter date?  If not, get the facts first and then decide.

Finally, if you don't like the bike and/or don't enjoy working on it, sell it now and focus on finding someone who does.

My opinion.

Cheers,

[MRieck]

Kibblewhite makes guides for the 500 and 550.

[clarkjh]

You should be able to still get the guides from Honda if I remember my last stop at the deal right.

James

[bryanj]

Genuine Honda manual or copy thereove and if you have another bike ready to work on "borrow" the parts from that