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Author Topic: Sludge in oil? Only on the cap?  (Read 8447 times)

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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #25 on: December 03, 2009, 12:03:14 AM »
Quote from: Hinomaru on December 02, 2009, 09:32:56 AM
As mentioned earlier in thread, it would be a good idea to check the oil tank breather/separator and vent hose to ensure its not clogged or restricted. Located on the rear of the oil tank and you can see the vent hose attached to the breather/separator fitting. The other end of the hose vents to the atmosphere.

(click on pic to enlarge)

Good point. I was fiddling running all the hoses after cleaning the carbs and kreeming the tank. Maybe I kinked it. I'll take a look in the morning.

One other thing maybe unrelated - Prior to the last round of work I was getting 42ish combined city/hiway. Fill up today and the odometer tells me 3 gallons at 93 miles - 31MPG. That's a fairly precipitous drop. Any possibility of these two things being related? I wouldn't think so but...
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Offline Gordon

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Re: Sludge in oil? Only on the cap?
« Reply #26 on: December 03, 2009, 12:08:00 AM »
Quote from: Hinomaru on December 02, 2009, 09:32:56 AM
As mentioned earlier in thread, it would be a good idea to check the oil tank breather/separator and vent hose to ensure its not clogged or restricted. Located on the rear of the oil tank and you can see the vent hose attached to the breather/separator fitting. The other end of the hose vents to the atmosphere.

(click on pic to enlarge)

This is what I'm leaning towards, too.  

Several years ago I was having the exact same creamy sludge problem on the oil tank cap.  As it turns out, when I rebuilt the bike I had replaced the crankcase and oil tank breather hoses incorrectly.  I don't remember exactly what I had done, and I can't say for sure how they're supposed to be on your bike because it seems like the breather/venting hose system changed almost every year on the 750, but once I got it right the sludge stopped appearing immediately.

I think I had the crankcase venting into the oil tank, or something along those lines, and it was forcing hot, moist air out around the oil tank cap, which was mixing with the film of oil already on the inside of the cap and creating that water/oil mayonnaise.  

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Offline 754

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Re: Sludge in oil? Only on the cap?
« Reply #27 on: December 03, 2009, 07:57:14 AM »
My 10 or 12 minutes is probably not enought to warm it.
 
 I prefer to run straight grades, but it is harder to find.
 There is pretty well no chabce it will get iver 60 degrees, so I would be safe with a lower weight.
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #28 on: December 07, 2009, 02:47:06 AM »
Quote from: Iggy on December 03, 2009, 12:03:14 AM
Quote from: Hinomaru on December 02, 2009, 09:32:56 AM
As mentioned earlier in thread, it would be a good idea to check the oil tank breather/separator and vent hose to ensure its not clogged or restricted. Located on the rear of the oil tank and you can see the vent hose attached to the breather/separator fitting. The other end of the hose vents to the atmosphere.

(click on pic to enlarge)

Good point. I was fiddling running all the hoses after cleaning the carbs and kreeming the tank. Maybe I kinked it. I'll take a look in the morning.

Think I found it. No kink in the oil tank breather but somehow I knocked this loose - probably putting the carbs back on...


I just tapped it back down so I'll see if that cures my mayo issue. Just enough heavy rain to get up under there maybe? Anybody have a pic of what's actually underneath that little sheath? It looks like a threaded tube but I don't want to pull it off to look just yet and can't seem to find any illustration of it.

BTW, I must be getting old cause I don't remember 30 degrees being this cold a couple years ago. Stupid winter...  ;D
« Last Edit: December 07, 2009, 02:49:15 AM by Iggy »
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Offline andy750

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Re: Sludge in oil? Only on the cap?
« Reply #29 on: December 07, 2009, 05:07:08 AM »
Quote from: Iggy on December 07, 2009, 02:47:06 AM
I just tapped it back down so I'll see if that cures my mayo issue. Just enough heavy rain to get up under there maybe? Anybody have a pic of what's actually underneath that little sheath? It looks like a threaded tube but I don't want to pull it off to look just yet and can't seem to find any illustration of it.


Underneath is the oil sensor switch.

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Offline MCRider

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Re: Sludge in oil? Only on the cap?
« Reply #30 on: December 07, 2009, 05:10:40 AM »
Not likely your problem. that is just a dust cover for the oil pressure switch.
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #31 on: December 07, 2009, 05:14:30 AM »
That's gotta be where the oil in the crevice is coming from. Is it supposed to be flush with the hole? You can see the threads. Possible it backed it's way out somehow?

I'll have to give it a couple turns and see if it's in there tight...

Hmmm, pretty sure that should be sitting flush with the case.


That's kind of disconcerting. The switch is one of the few things I never took a wrench to on this bike.
« Last Edit: December 07, 2009, 05:27:58 AM by Iggy »
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Offline MCRider

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Re: Sludge in oil? Only on the cap?
« Reply #32 on: December 07, 2009, 05:27:38 AM »
Quote from: Iggy on December 07, 2009, 05:14:30 AM
That's gotta be where the oil in the crevice is coming from. Is it supposed to be flush with the hole? You can see the threads. Possible it backed it's way out somehow?

I'll have to give it a couple turns and see if it's in there tight...
Its a tapered pipe thread, gets tighter as it turns. Don't try to bottom it out or you'll break something.

It could be broken and leaking, if so tightening won't help. You'd have to replace it.

FYI: Stains in that area of the engine are most often fuel.
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #33 on: December 07, 2009, 05:33:13 AM »
Its a tapered pipe thread, gets tighter as it turns. Don't try to bottom it out or you'll break something.

It could be broken and leaking, if so tightening won't help. You'd have to replace it.

FYI: Stains in that area of the engine are most often fuel.
[/quote]

Still lights up the oil light at this point turning the key. Does it sit flush for everyone else?

It's supposed to be clear and dry the next few days. Maybe some foot powder is in order.

I really need a garage - doing anything but throwing a leg over it on the side of the road is a pain in the ass ::)
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Offline MCRider

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Re: Sludge in oil? Only on the cap?
« Reply #34 on: December 07, 2009, 05:43:54 AM »
Quote from: Iggy on December 07, 2009, 05:33:13 AM
Its a tapered pipe thread, gets tighter as it turns. Don't try to bottom it out or you'll break something.

It could be broken and leaking, if so tightening won't help. You'd have to replace it.

FYI: Stains in that area of the engine are most often fuel.

Still lights up the oil light at this point turning the key. Does it sit flush for everyone else?

It's supposed to be clear and dry the next few days. Maybe some foot powder is in order.

I really need a garage - doing anything but throwing a leg over it on the side of the road is a pain in the ass ::)
[/quote]
The powder test would be good.

Back to your origianl question, I think you're probably seeing a natural phenomenon. I wouldn't worry about it if you are changing the oil regularly and not shooting water up under the cap with a power sprayer. That's just my $.02 and OCICBW.

Very few bikes have the ability for us to look at the oil after a run as they don't have tanks. Wonder what we would see.
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #35 on: December 07, 2009, 05:54:55 AM »
Quote from: MCRider on December 07, 2009, 05:43:54 AM
The powder test would be good.

Back to your origianl question, I think you're probably seeing a natural phenomenon. I wouldn't worry about it if you are changing the oil regularly and not shooting water up under the cap with a power sprayer. That's just my $.02 and OCICBW.

Learned my lesson with power wash this summer  ;D

Got about 2500 miles on it since getting it back on the road this March. One oil change a couple months ago when I Kreemed the tank. The oil/fuel in the crevice dates to just after Kreeming the tank. It'd be nice if there was some cause and effect there but probably not.

Seems to be running fine - if a bit rich.  Let the fiddling commence!
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Offline TwoTired

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Re: Sludge in oil? Only on the cap?
« Reply #36 on: December 07, 2009, 11:51:01 AM »
You've had some pretty good pointers about checking the engine/oil tank breather tubes.  I wonder why you don't follow up on that and make sure they functioning correctly?

The 550 is a little different from the 750, the 550 being wet sump.  But, it has a crankcase breather, too.  It has a foam element that gets soggy with water from the condensation in cold/rainy weather.  When it gets too restrictive with water, there occurs lots of brown mayo on the dipstick cap at the back end of the engine.  This is my signal to clean/clear the breather element (again), and then go run the bike hard for 20 minutes after the motor gets hot.  This usually clears the brown mayo formation, as long as the OAT is above, say 40F. 
(The full Vetter fairing with lowers, and some insulated ski pants, make the ride rather enjoyable.)

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Lloyd... (SOHC4 #11 Original Mail List)
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #37 on: December 07, 2009, 12:03:23 PM »
No kink in the oil tank breather or engine breather that I can find. Time to schedule Pop's garage for some quality time with the bike. I'm betting it's semi normal behavior for this machine at this point but there's some stuff I want to attend to like losing the cheap points I bought etc.

On the temp: I think I've just lost my Gordon Liddy mind set and now I mind that it's cold.

Thanks all for the advice!
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Offline TwoTired

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Re: Sludge in oil? Only on the cap?
« Reply #38 on: December 07, 2009, 12:09:07 PM »
Just to get mired in details...  ;D

While good to look for kinks.  It is even better to prove there isn't some blockage in the tubes that perhaps insects have made while the bike was parked.

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Lloyd... (SOHC4 #11 Original Mail List)
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Offline ev0lve

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Re: Sludge in oil? Only on the cap?
« Reply #39 on: December 07, 2009, 12:16:00 PM »
That's a point. We have some VERY industrious wood spiders in these parts although I'd hope they'd be smart enough to find a nearby wood pile instead of my machine. They are pretty disturbing Alien style when they get in the apartment ;D
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