Topic: oil leak

[ateamsam]

Hey All,

I have a 1974 CB 550 that is mechanically sound according to two different mechanics.  But for some reason there has always been a slight oil leak somewhere that seems to dirty the underside of the bike pretty nicely.  One mechanic, the one who specializes on these old bikes, told me not to worry about slight leaks (is that odd?).  I want the bike to shine and have aspirations of having the engine painted, but assume that I should get this oil situation sorted first so that a new paint job wouldn't just get mucked up by oil.

Here is my question:  How do I figure out where the slight leak is coming from? I figure maybe I should just scrub the whole thing down and just inspect it every time I ride it.

If it needs new gaskets, how much would that cost to have a professional do it (I work full time, go to school at night, and have no tools)?

I'll take some pics later today if I can so you guys and can help diagnose this.

[Johnie]

The only way to properly identify an oil leak is to clean the whole area. Some guys then put baby powder in the area and you can find the leak. It could be as simple as the oil pan gasket or neutral switch seal. Both are easy to fix. Or it could be oil running down from the top end, stator cover, stator rubber grommet, tranny cover, tach seal, etc. Clean it up and then start looking...good luck with it.

[MCRider]

Its not odd for a mechanic to say don't worry about slight leaks, on a very old machine. Many here have lamented how a simple oil leak fix job led them down a path they wish they hadn't taken. But this usually revolves around rebuilds and upgrades. "If your this far you might as well do this too" type thing.

On the otherhand, if you want it to be oil tight it can be. Just set your goal ahead of time and stick to it. Unless you secretively want to do more.   

[Johnie]

Yes...take heed to what MCRider says. Over the years there have been a few who went deep into the motor and ended up with more problems after the rebuild than to just fix a oil leak. Keep in mind these are vintage motors and will leak some oil. That does not mean you can not live with it. Most of us have a slight oil leak on the head gasket. That is a common Honda deal on these bikes. No need to tear the head off unless it gets real bad.

[ateamsam]

Its not odd for a mechanic to say don't worry about slight leaks, on a very old machine. Many here have lamented how a simple oil leak fix job led them down a path they wish they hadn't taken. But this usually revolves around rebuilds and upgrades. "If your this far you might as well do this too" type thing.

On the otherhand, if you want it to be oil tight it can be. Just set your goal ahead of time and stick to it. Unless you secretively want to do more.   

Good point.  The bike doesn't smoke or anything of the sort.  I'll clean it up tonight and tomorrow and post some pics before I head to a motorcycle show in Milwaukee.

[Mayor08]

Were you at Rockerbox??  We could have compared oil leaks!!  My started the a few days leading up to the weekend but can't find it yet plan on doing the baby powder trick tonight

[rickmoore24]

A quick easy check is the oil chain luber on the front sprocket. I'm actually not sure if your 550 has one but I had a little tiny leak after a full bottom up engine rebuild  on my K2 750 and that's what it ended up being. Oil seeping at the bottom of the cover on the gear selector side. Screwed in the little stud at the center of the sprocket and the oil stopped flowing! i have an o-ring chain now so the oil luber isn't needed. Try that if you haven't already.

Rick

[ateamsam]

i actually haven't tried anything yet since i'm in finals week for my summer classes. 

Were you at Rockerbox??  We could have compared oil leaks!!  My started the a few days leading up to the weekend but can't find it yet plan on doing the baby powder trick tonight

I wasn't there.  I planned on going up, about a 2 hour ride, but all my "friends" bailed on me.  I ended up going to Rockford to see another 1974 CB550 (way better condition than mine).  How was it?

[Motoguy23]

If the harley guys can deal with a puddle under their bikes then you should be able to deal with a little dust collecting.

Oil leaking from the head is common, the only thing you can do there is make sure your head is torqued down correctly.  I have an oil leak from what I think is my tappet caps that got over the front of the motor so I replaced the o-rings. That is a very simple job and all you need is a 17mm wrench and about 10 minutes, and the o-rings of course.

[DedHed]

Hey ATeam,
I had the same issue on my 750 K4. It had not been cleaned by the PO for some time. I cleaned mine - the bike lost about 37 1/2 pounds - degreaser and a power washer on low settings did the trick. I found my leak is with the oil pan gasket. I called the PO and asked when the last time he changed that gasket, his response, what gasket. YIKES!

As yours does, the bike runs great - no smoke, no massive leaks, just a very small puddle under the side stand when I ride for a while then park it. It's really not bad at all, I feel kind of like a dog... I leave my mark where ever I go.

Another issue for the brain trust here....
If I forget to set the petcock to "Off" and leave the bike sitting for a while a decent amount of fuel will drain out of (I'm guessing) the fuel overflow tube. I can't figure this one out... Bad / dirty float in the carbs? IS this "What they do" when the fuel valve is left open?

After changing the oil, filter, plugs and cleaning the screen this Saturday, I will tackle the fuel issue with a professional (Joe Bruton).
Safe riding all!
Phil

[MCRider]

The oil pan gasket doesn't ever need to be changed unless you remove the oil pan. No need to do that unless you've got the engine out and or want to inspect the oil pump. I'd be suspicious if he HAD replaced the gasket.

re: Petcock. Yes the old gravity feed petcocks needed to be turned off or you suffer the CHANCE that fuel will overflow the float bowls. This is most likely to happen if parked on the sidestand and the floats hang up. If on the centerstand, and the flaot valves are working properly, you should noit suffer from fuel overflow.

If you have the overflow onto the ground, you may also have overflow into the crankcase. This comes from actual wet gas overflowing the overflow, and running into the cylinders, or gas fumes condensing on the cold cyl walls and running into  the crankcase.

Check your oil if the level is higher than expected it may have gas in it.

And turn your gas off if parking for more than a few hours. I would turn it off, when i remembered to, as i am entering the garage, with the engine still running, to pull a little out of the floats.

[ateamsam]

The oil pan gasket doesn't ever need to be changed unless you remove the oil pan. No need to do that unless you've got the engine out and or want to inspect the oil pump. I'd be suspicious if he HAD replaced the gasket.

re: Petcock. Yes the old gravity feed petcocks needed to be turned off or you suffer the CHANCE that fuel will overflow the float bowls. This is most likely to happen if parked on the sidestand and the floats hang up. If on the centerstand, and the flaot valves are working properly, you should noit suffer from fuel overflow.

If you have the overflow onto the ground, you may also have overflow into the crankcase. This comes from actual wet gas overflowing the overflow, and running into the cylinders, or gas fumes condensing on the cold cyl walls and running into  the crankcase.

Check your oil if the level is higher than expected it may have gas in it.

And turn your gas off if parking for more than a few hours. I would turn it off, when i remembered to, as i am entering the garage, with the engine still running, to pull a little out of the floats.

great advice, thanks!