Topic: First start. Runs smooth. Smokey breather??

[evopgt]

Hey guys.  My batttery came today so I four it in and cranked it over.. it fired right up to my surprise and ran smooth as silk. First time running in 20 years.  It has some smoke coming out of the breather filter though... some out the exhaust too.  Breather smoke is like a darker grey. It's not a ton just an annoyance. The hotter it got.. the smokier it seemed to get. I let it run for about 30 minutes.  Until I shut it down.  Is this normal for a first start up?? Will it go away ?? Or what could be the issue??

[Ridem32]

That's a long time not to run a engine.  I would get out and run it but not hard. Put a few miles on it. The rings might seat back. Some is going to be old cracked and dried out valve stem seals.


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[DaveBarbier]

Also, it's not good to let an air cooled engine run stationary unless you have a strong fan pointed at the headers.


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[evopgt]

Gotcha, may need new valve stem seals.. The second time I ran it after this post ,, No smoke at all.. I only ran it like 2 min. Though.  is there anything that I might as well do while I'm in there?? For now, I'm gonna keep workin on some small stuff on the bike and get it on the road.. then hone in on engine perfection!!

[Lostboy Steve]

Gotcha, may need new valve stem seals.. The second time I ran it after this post ,, No smoke at all.. I only ran it like 2 min. Though.  is there anything that I might as well do while I'm in there?? For now, I'm gonna keep workin on some small stuff on the bike and get it on the road.. then hone in on engine perfection!!

If my bike sits for a while I get breather smoke until it warms up. I solved the problem by routing the breather back into the intake where it originally was.


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[Deltarider]

I solved the problem by routing the breather back into the intake where it originally was.

What problem? You may have created one. Check regularly that vapour doesn't wetten your aircleaner element. And 'originally' (CB500) it wasn't even there. For those that have enough of that typical soft light brown spot in the paper aircleaner element cf p. 170 of the manual https://www.classiccycles.org/media//DIR_1653304/DIR_1653404/DIR_1653507/ecc6759db0a214d5ffff8825ffffe41e.pdf how to reroute.

[jonda500]

Interesting shop manual addendum Delta! Love steps 5 & 6 of carburetor removal:

5.Loosen the carburetor insulator bands and the air cleaner connecting bands. Take the carburetor assembly out.
6.To install the carburetor assembly, reverse the removal procedure.

See how easy it is? (ha ha haahaa  )

On a more serious note, I wonder why the Australian model is a whole kilogram lighter?
John

[robvangulik]

Did no-one notice the exceptional torque figures given for  brakedisc mouñting nuts?
I misread it, expected kg/m, and was written as kg/cm

[markreimer]

Breather smoke after a long sit can often be condensation. Bike sat for 20 years, I presume you changed the oil before starting it up? Get fresh oil in there, do all the proper maintenance tune-ups - cam chain tension, valve clearance, points gap and timing etc, plugs, battery, fresh gas with a clean carb, then go ride the piss outta it.

If it's sat that long, it is a good idea to dump a bit of oil into the valve adjustment caps to ensure the top end has oil right from the get go. Since you've started it already, it's a bit late for that.

By the way, what kind of SOHC4 bike is it?

I get breather smoke regularly, out the engine breather as well as the oil tank vent ('74 cb750). The tell tale sign of vapour is opening up the oil tank cap and seeing some white foamy junk on the bottom of the cap, which is moisture build up. After a hard 60 mile ride it all burns off and the smoke goes away. The key is getting it up to full operating temperature and keeping it there long enough to burn off that moisture. There are even some out there who think it's not a wise idea to go on repeated short trips because the engine doesn't get hot enough to burn off the moisture. I'm not that extreme, but I see the point of the argument.

[Deltarider]

There are even some out there who think it's not a wise idea to go on repeated short trips because the engine doesn't get hot enough to burn off the moisture.

This^.