Non-Oil-Burning Oil Leak from Exhaust Manifold

[Roostabunny]

Yikes - I've got a 1981 GS850G that I use for my daily commute. I've ridden once or twice in the past, but this is the first bike I've owned, and had it for about three months.

Yesterday I started seeing smoke when I stopped at lights. A quick visual showed that oil was dripping from the vicinity of the #4 exhaust pipe down onto the hot pipes below. I saw a very similar post, but that fella's bike had been burning oil, too.

It doesn't appear that my bike is burning oil (no black smoke from the exhaust) so I was mystified when the oil also didn't seem to be coming from the head gasket. I cleaned up the engine (even sprayed some foot powder). I could see the drip come back before I even started it up, and it was definitely originating UPHILL from the head gasket. When I started it up, it started dripping in earnest, and by the time the engine was warm (about 10 minutes) I probably had about a tablespoon worth of oil on the ground.

The bike has about 35,000 miles, runs smooth, and idles nicely at around 1000rpm. About two weeks ago I changed the oil (dino 10W-40) and filter before going on my first ride in the mountains over the weekend. I put about 300 miles on at that time, and got the bike up over 100mph for the first time (according to my FJR1300-riding buddy, who's speedo actually goes over 85). Don't think that hurt anything, but I mention it just in case.

I have three (maybe four) questions, but welcome any other comments as well...

1. Obviously, any idea what's going on? I'm willing and able to swap some gaskets (adjust the valves while I'm at it, maybe) but this seems to be something else.
2. This is my daily transportation - can I keep riding as long as I keep an eye on the oil level and don't drop the thing at a stop light due to oily boots and pull my groin?
3. I'm mechanical and (more importantly) have a buddy who's a police bike mechanic (20+ years experience with older bikes - including Suzuki) with a well equipped home shop. If you have a diagnosis, any idea how long we'll need we'll need to get it fixed? In other words, and can we fix it on a Saturday and about how much do you think I'll be out in parts?

Thanks a million! 10 years ago I found GS Resources when I started having an interest in motorcycles and decided that I had to have a GS. It only took me 10 years to actually get around to buying one, and boy was I relieved when you guys were still here!

 

[Roostabunny]

BTW, I should have explained that the picture is post-foot spray. Just to the right of the exhaust pipe, you can see the wet spot forming before I started the bike.

This picture is before I wiped the pooled oil off the fins and spayed it down. And again, hopefully you can tell from the pics, but these fins are north of the head gasket.

 

[Nessism]

My guess is valve cover leak. Easy fix if you can find a gasket. Of course, this is just a guess, you need to study the situation more closely.

 

[t3rmin]

If the 850 has the mechanical tach sender up there, that'd be the first thing I'd check.

 

[waterman]

I have to agree with above, most likely a valve cover gasket failure or a leaking tach drive. As suggested, fairly straightforward repair that you can perform yourself. As far as driving with leak, use your own judgment; tablespoon per 10 minutes drive maybe acceptable if only going for short ride.

I would acquire a valve cover gasket and then check/adjust valves and replace gasket. Just watch when replacing valve cover bolts to use torque wrench to tighten, way to easy to strip or break bolts. Most certainly this could be fixed on a Saturday, call buddy and make a day of it.

 

[bwringer]

Leaky tach cable fitting is my first guess. It's the most likely explanation, it's the easiest and cheapest to deal with, and it's something every GS owner needs to fix at some point anyway.

The fix is easy-peasy. Here are Ye Complete Instructions, with part numbers and everything:
http://bwringer.com/gs/tachcableseals.html



If it's the valve cover gasket, I highly recommend a RealGasket -- it doesn't leak, and can be reused for a lifetime:
http://realgaskets.com/files/motorcycle.htm

Make sure you get the breather cover gasket, too!

 

[Roostabunny]

I think that my tach cable may be leaking. It was definitely leaking before I replaced the tach cable, and since then I've seen the posts and tutorials on that and added it to my to-do list.

I've also been keeping an eye on my valve cover gasket. I think both parts are seeping. They're still seeping - I can see the starts of new seep since I cleaned it up this morning.

But this is new. And it's not a seep. I just rode home and it's a good double drip from the manifold and the fins just to the right (from the front). Can I pull the ring from the exhaust connection to get a better look?

 

[Suzuki_Don]

Dont snap the exhaust flange bolts/studs off. They are very fragile. If you snap them the usual solution is to remove the cylinder head to have the broken remains removed (usually by a machine shop). Read other posts on this site on this issue before you attempt to remove the exhaust bolts.

 

[Roostabunny]

Thanks for that tip, Suzuki Don. My ham hands could have made a real mess not knowing those bolts were easy to break. Will read up and proceed with caution.

I'd read bwringer's terriffic tutorial on the oil seal for that tach gear and Basscliff's excellent write-up on valve adjustment that includes info on Real gaskets for both the valve and breather cover. Can we have you guys give Chilton and Clymer some photography lessons? I'll order those parts presently and see what happens once I get it set.

I'm hoping my friend's got a shim set I can poach from. Maybe I'm paranoid now, but I feel like I'm hearing some valve clatter, and if I'm replacing the gaskets, I might as well adjust the valves while I've got the thing apart, right?

For that matter, how much extra time would be involved in replacing the base gasket?

 

[Roostabunny]

Forgot to mention - even though I'm planning to do that tach gear oil seal, there's clearly oil that looks like it's flowing from behind the exhaust flange, but none flowing from the tach cable. As I said, more of a seep.

Just for sake of argument, let's say I was done replacing the valve cover, breather, and tach cable gaskets - is there any way that oil could still flow from the exhaust flange without showing up in the exhaust as black smoke as well?

 

[Dink]

Forgot to mention - even though I'm planning to do that tach gear oil seal, there's clearly oil that looks like it's flowing from behind the exhaust flange, but none flowing from the tach cable. As I said, more of a seep.

Just for sake of argument, let's say I was done replacing the valve cover, breather, and tach cable gaskets - is there any way that oil could still flow from the exhaust flange without showing up in the exhaust as black smoke as well?

No!!!

Dink

 

[Suzuki_Don]

1. If by base gasket you mean the one between the cylinder block and the crankcase then that is a big job as you have to remove the cylinder head and the cylinders. Then you have to refit the pistons into the bores as the barrel is inserted back on to the crankcase. The cam timing has to be redone, etc. Unless you are losing a good amount of oil from the base gasket I would not worry about replacing that one.

2. If you are removing the valve cover to replace the valve cover gasket (the one between the cylinder head and valve cover) then it will only take 10 mins to check your valve clearances once the valve cover is off. Depending on your results (the clearances should be 0.3mm to 0.8mm) you will then only change the shims that require it. Contact STEVE for a spreadsheet that makes recording your clearances easy and does the maths (that's OZ) for you.

3. Black smoke from of the exhaust is a rich carby mixture not burnt oil. Burnt oil from the exhaust is always a blue colour. Smoke can only come out the exhaust if it comes from inside the cylinder. It cannot leak from the outside of the cylinder head and get inside the exhaust. If smoke is coming from the exhaust it is a rich mixture, worn cylinders or worn valve guides or valve seals.

Hope this helps. have another look after you have cleaned it up. Wash it up with degreaser, or petrol or whatever to remove all traces of oil and then look closely to see the exact spot the oil is coming from. Look to see if it is coming from behind something or between fins or whatever,

GOOD LUCK.

Cheers

Don

 

[BassCliff]

Mr. Roostabunny,

That really looks like that same rusty-brown mess my tach cable seal was making all over the front of my motor. Then I used Mr. bwringer's tutorial to get it fixed and there's no more mess. In the picture, are we looking between #2 and #3? I see that brown gunk all over up higher than on the fins with the pool. I concur with the others. Replace the tach cable seal first. It's about a half hour job. Just keep track of which way the old one comes out and put the new one in the same way. I didn't pay attention and had to really study Mr. bwringer's pictures to reassemble it properly.

BTW, I didn't mention part numbers in my valve adjustment pictorial because this procedure is so similar between all the 8 valve GS motors. But you can find it easily enough at realgaskets.com. Yours should be the RG-GS850-G1 part for the valve cover and RG-SBC-2 for the breather gasket.

Thank you for your indulgence,

BassCliff

 

[Roostabunny]

OK, I've ordered the gaskets for the Valve and Breather covers (from Real) and after checking with my local shop I realized it's going to be cheaper (even with shipping) to get the tach cable parts online, so I'll order those next and get the parts for the Cam Chain tensioner re-seal while I'm at it to save on shipping.

Meanwhile, what about the head gasket? Am I looking at the right part for $75? Should I consider doing that with the valve adjustment? The idle sounds fine - do I need a compression test to know?

Oh, speaking of pressure - news flash. I had oil up around the #4 spark plug when I got home yesterday, and I noticed that there were little bubbles forming there, so something's coming out over there. If oil is leaking from the spark plug threads, then I'm really mystified by the lack of smoke. I haven't had a chance to re-clean and watch that area yet since yesterday, and I chickened out and drove a car today. No sign of oil by the other plugs.

Can I use a regular deep 22mm socket (which I already have) to take a look at that plug or do I need to pick up a 22mm spark plug socket?

You guys are saving my sanity here - thanks!

 

[Roostabunny]

As always, forgot to say something...

1.) Thanks, Mr. Basscliff for the Real Gasket Part #'s on the 850.
2.) The view in the pic is between 3 and 4. I think you're seeing rust residue. Either way, everythings happening on the right side of the bike, and now that I put the bubbling spark plug into the mix seems to be all about cylinder #4.

Now I'm anxious to get home so I can clean it up again and watch that plug. I want to pull it out, too, so I can hopefully get an idea of what the heck's going on in there.

 

[Nessism]

It's very difficult to fix something if you don't know what's broke. For that reason I suggest a complete engine degreasing to remove all the oil followed by drying. Gunk spray cleaner is cheap and works well. Some people prefer Simple Green since it stinks less (it's less effective as a cleaner in my experience). In either case, you need to remove all the old oil, dry the engine, followed by running the bike on the centerstand while you watch the engine closely to pinpoint the source of the leak(s).

In terms of parts, I recommend the stock factory parts for gaskets unless you need to pull the top end (cylinder head/cylinders). In that case, purchase a complete gasket kit since it will save you a lot of money (check Z1 Enterprises). Those Real Gaskets are somewhat tempermental in terms of the torque they require thus I don't recommend them unless you have a fair bit of mechanical experience and/or an appropriate torque wrench.

Good luck.

 

[Roostabunny]

Thanks Mr. Nessism.

So here's my shopping list for the Auto Parts store...

• 18mm Spark plug wrench (from the forum I'm pretty sure that's the one I need, not the 22mm I mentioned before)
• Gunk spray cleaner
• PB Buster (if they have it)

I agree, my "troubleshooting" is all over the map. I'm learning what to look for.

Here's my thought...

1. Pull a couple of plugs, both to see what's there and to compare between #4 and the others.
2. Put the plugs back and de-oil the outside of the engine
3. When it's dry I may try the spray powder again - that seemed effective
4. Start her up and watch like a hawk
5. Post the results.

Any other thoughts or specific things to look for? My only concern is that the main leak seems to originate from behind the exhaust flange and I can't seem to see back there - even with a flashlinght. Hopefully I'll find out otherwise, but that's why I have PB Buster on the shopping list. Thanks to an earlier post one thing I'm not going to do is bust an exhaust flange bolt hunting an oil leak.

As for the Real gaskets, I think I'll be OK. I'll be using a friend's shop and he's a motorcycle mechanic by trade (lucky me) and has a good torque wrenches.

BTW, I posted a picture of my Tach sender area. Gunk, but no flow.

 

[bwringer]

The spark plugs (NGK B8-ES) take a 13/16 or 21mm socket. (Don't fart around with fancy expensive spark plugs. B8-ES have been well-proven to work the best in these engines. Stocking number 2411, available for $1.79 each at most auto parts stores that aren't Autozone.)

Also, you seem to have the idea that there's high-pressure oil just waiting to burst out under every metal surface of this engine. Removing an exhaust flange will not allow you to see or learn anything new -- there's no mysterious oil passage back there.

The oil feed and return passages for the cylinder head are at the four outer corners -- note the acorn nuts with the copper sealing washers under them. (Whenever you remove the valve cover, it's a good idea to re-torque all the cylinder head nuts.)

Once the oil has made it to the cylinder head, it can only escape via the tach cable fitting, the valve cover gasket, or the breather cover atop the valve cover.

It's also worth remembering that these roller bearing crank engines use very little oil pressure -- oil is pumped through the engine via relatively large passages, so normal pressure is something like 1 to 3 psi.

However, many a mechanic has been driven batty because escaped oil ends up flowing to the oddest places on these engines.

Your tach cable fitting is DEFINITELY leaking, and oil from there will quickly end up all over the engine in surprising places and quantities. If it pools around a spark plug that's not completely torqued down, you might see the bubbling you were talking about, but the two issues are not related -- there's no oil passage or seal anywhere near the spark plug.

The valve cover gasket might be leaking on the back side, but it would be very unusual for it to start leaking out of the blue as you describe. It's pretty normal for a tach seal leak to get worse quickly.

One other issue to be aware of is that a clogged breather tube can sometimes cause the normal pressure inside the engine from blowby to build up and force oil out through weak gaskets and seals. Check the large tube between the breather cover at the very top of the engine and the airbox, and make sure it's not pinched, kinked, or clogged.

 

[waterman]

As Bwringer states, that tach drive is leaking in last picture. I can also see that the bolt the secures the exhaust flange to the head for #3 is not stock and has been replaced. It has nothing to do with oil leak but unless your bike has aftermarket exhaust would wonder what previous owner had done to engine. Not trying to raise alarm bells, but makes you wonder.

 

[Roostabunny]

Eureka!

Eureka!

Eureka!

I found the leak and doff my helmet to all.

It was indeed the valve cover gasket. I'm almost embarrassed to post the photo, because not only is the leak really obvious, it's not even in any of the spots I cleaned.

I did however, pay more attention to detail after I cleaned it and noticed that the spaces between fins next to the #4 exhaust flange passed all the way through to the space where the #3 spark plug resides. I then I got up and noticed that there was oil pooled around the #3 plug, and thought, "huh, better shine my light in there when I start it up."

Low and behold, 3 minutes after start-up I had a the nice caramel river in the picture. Lesson learned - When the gasket's shaped like an H, you can't be satisfied with a detailed inspection of only the outer perimeter. Rookie mistake, I guess.

Mr. Bwringer, I appreciate the oil info. I had imagined that oil was trying much harder to escape than a mere 3 psi. And I'll check that breather.

So my gaskets are ordered (Valve cover, breather cover, cam chain tensioner, and tach), and I'll take care of all of them and then give that engine an extra thorough cleaning so that I can really enjoy having all the oil in the inside.

Meanwhile, Mr Waterman, I noticed those bolts myself when I was down there because they look like stainless. Simplest theory is that the head was off at some point and after removing the stock bolts once the owner decided to go with something that wouldn't rust. I almost did the same thing when I replaced the intake book o-rings, but went for plain black hex nuts instead. What do you think - will those stainless bolts be a problem?

More than anything thank you all for sharing your vast knowledge. I would have lost sleep and/or broken something in my haste and ignorance. Instead I soak up your knowledge like oil into a nice clean air filter element. :-D

I'll update the thread when these parts arrive.