Topic: Smoking

[PheNam]

What's going on guys. I hope you are all staying warm this winter. I hadn't had my bike running for about 3 months due to being out of town, work, etc. Long story short, bought a 76 CB550 in the Fall and had some electrical problems off and on due to age. So far it has been mechanically sound but I am not one to really know as this is my first bike.

In any case, I started it and let it run both yesterday and today for about 10-15 min each time. Idles high at 4000rpm. I am attributing this to the weather? I have heard through urban lore that an engine runs more efficiently during the winter?

Also, around the time 10 min mark once the bike is warmer, smoke starts coming out below the battery. I have uploaded a video to check out. Suggestions welcome. Either way I am looking forward to this year's riding season. Cheers

First half of video left side, second half right side:

[goldarrow]

That's a lot of smoke.  What does it smell like?

[PheNam]

You know what, I have a cold so I couldn't breathe through them if my life depended on it. It is pretty cold here in Chicago so I took a quick clip and closed the garage.

[calj737]

I would discourage you from letting it idle for 10-15 minutes. These are air-cooled engines and they depend upon air flowing over the engine to cool them. Despite the ambient temperature, they need airflow.

[Airborne 82nd]

I would discourage you from letting it idle for 10-15 minutes. These are air-cooled engines and they depend upon air flowing over the engine to cool them. Despite the ambient temperature, they need airflow.

+1 and at 4000

[LesterPiglet]

Load of bollocks about idling. The bike will stop itself if it overheats. It won't overheat in temps below 15c after 15 minutes.
I live in Northern Ireland... next stop Iceland? My bike overheated once in a traffic jam. You lose the clutch then you know to turn it off.
That bike isn't idling by the way. It's around 3k.

[ekpent]

Urban legend--Please fix your idle problem for starters.

[wjustinleigh]

It is smoke or steam?  Where is it coming from - maybe the exhaust port from the head?  If it's missing the exhaust tube (like many/most) it seems like it could be throwing the smoke straight back, hits the battery cluster and comes out the bottom.  If it was from something electrical I think you'd smell it even with a cold.  Is the fuse OK and still being used (i.e. not wired around)?

If you just turn your idle screw down will it hold an idle at 1K?

[martin99]

Do these have a breather tube coming from the cam cover like the 750s? Probably should be routed to the airbox. That's what my 750 does as I have the breather pipe routed to air and it looks worse in cold weather.
After three months sitting you might have some condensation in there thats burning off. Personally I'd drop the idle, have a good look round to make sure it isn't about to spontaneously combust, and take it for a ride.
 

[NobleHops]

Do these have a breather tube coming from the cam cover like the 750s? Probably should be routed to the airbox. That's what my 750 does as I have the breather pipe routed to air and it looks worse in cold weather.
After three months sitting you might have some condensation in there thats burning off. Personally I'd drop the idle, have a good look round to make sure it isn't about to spontaneously combust, and take it for a ride.
 

Spot on, this is the likely culprit, breather tube on my 400 is in that neighborhood, and for certain, every time you run the bike for 5 minutes you have been ADDING more condensation to your engine and oil. If you run it again check the oil after a few minutes and you will likely see that it looks like chocolate milk with all the water mixing with the oil. This is why you're better off not running it unless you can really get it warm enough to burn all that off.

[NobleHops]

P.S. Stick your fingers into the "smoke" for a few minutes and they should feel mostly damp, slightly oily, if it's condensation.

[Bodi]

"Idle" at 3-4000 rpm is not good. It is better for charging the battery, I suppose, but idle should be 1200 rpm or so (I did not check the CB550 manual so it could be spec'd lower). If it's so high because it refuses to idle lower, fix that problem first.
Extended idling will absolutely overheat an air cooled CB550 engine, and it will not "shut itself off" when that happens. I don't think it would kill an engine, especially if idled (at 1200 rpm!) for 15 minutes from cold. Idling for 15 minutes after a long highway ride would be a really bad idea. running 3-4000 RPM is not "idling", and heat generation is much higher. If it's set at that speed because the idle is too lean, heat generation is again much higher.
The smoke is either steam or burning oil. When the cylinders and head overheat (not unlikely for you) the oil film on the cylinders starts to smoke, and the oil splashed around the head starts to smoke. There is a blowby vent at the very top of the engine, it's supposed to connect to the airbox so fumes are sent through the engine - that tube is often disconnected from the airbox or just removed. That's the apparent source of the smoke/steam, you can check by removing the tank.
It could also be steam. Water condenses when the engine is run cold, and it boils off when the engine heats up. That should come out the top vent and go into the airbox as well.
Your video looks like steam but I don't know for sure. Oil smoke usually comes out the exhaust as well, is it smoking? Steam also comes out the exhaust but it's pretty obviously steam - much like chimney steam it disappears into clear water vapour within a second or two except in very cold air. Actual smoke stays smoky as it blows away.