Non-Oil-Burning Oil Leak from Exhaust Manifold

[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!

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.

[Roostabunny]

Parts on the way

OK, all parts ordered and the waiting game begins...

Bikebandit usually takes a while (half moons), and I don't want to go a whole extra week if their stuff doesn't show up by the weekend. My Real gaskets should be here no later than tomorrow. So, here are my questions...

1. Are the Real gaskets as re-usable as they say? Can I clean things up, put the gaskets in there, and then adjust the valves (and replace the half moons) later without replacing the gasket again if I'm careful?
2. Alternately, can I use a high-temp rtv sealant in that 1/2" space that's leaking in the current gasket to slow the flow for a couple of days till I can get everything ready for the job? The leak was just too fast for me to feel comfortable riding, and it was pretty tough on the old trouser legs/shoes.

Meanwhile, I'm pretty excited to declare war on my oil leaks. Here's what's coming after a flurry of ordering...

• Valve and breather cover gaskets (Real)
• Valve Cover half moons (Bike Bandit)
• Tach gear oil seal parts (Bike Bandit)
• Cam Chain Tensioner rebuild parts (Bike Bandit) - Anyone know the mounting bolt sizes on this thing? I hear there are two sizes and want to get stainless.
• Carb boot o-rings and stainless bolts (Cycleorings - not oil-related, but I read a thread yesterday that made me realize my NAPA rings wouldn't last, and I'll have the carbs off when I do the Cam Chain tensioner anyway.)
• Oil filter and filter cover o-ring (Bike Bandit - it's about time anyway)

Hope it arrives before the weekend! [-o<

[bwringer]

1) Yes, you can re-use RealGaskets for a lifetime. Mine has something like 8 or 9 valve checks on it.

Just make sure you don't overtorque the bolts. 15 inch-pounds is barely finger-tight. In fact, torque wrenches that can read that low are fairly rare and expensive. Just tighten the bolts finger tight, then watch how much the gasket is compressed -- maybe another half-turn or so would be enough to compress the gasket by about a third of its height or less.

2) NO! RTV goes in the trash can or your old broken down Chevy, not on your GS. It wouldn't do a thing to seal this leak anyway.

Someone will be along shortly to call me a silicone Nazi... RTV has certain uses, but only in vanishingly small amounts (no thicker than what you can see through), and only to deal with special problems or emergencies, like badly dinged-up gasket surfaces. In these cases, a nonhardening sealer like Hylomar is a far better choice.

3) On a GS850, the tensioner mounting bolts are two 6mm X 25mm and one 6mm X 20mm. (bolts are spec'd by thread diameter X length of threads -- you don't include the head of the fastener). Buy lots of extras -- stainless is strangely addictive. :-D


4) You can get a very nice oil filter and o-ring from your local Napa store -- PS4931, I think (or let them look it up). It's made by Wix and is better quality than the more common Fram filters. You can re-use the oil filter cover o-rings, but not forever. I normally install a new OEM o-ring once a season, with the first oil change in the spring. Most stores have one or two in stock.

[Roostabunny]

1.) Good news. So if I'm delayed on the valve check because I couldn't borrow the tools and shim set, I can still get back on the road with my new gasket. Thanks for the torque tip.

2.) Funny. Reminds me of the time I used belt dressing to silence a squeaky belt on a car years ago. I brought it to my awesome mechanic and when I picked it up he was fuming because "Some a**hole sprayed the sh*t out of the belt with belt dressing". I informed him sheepishly that I was the a**hole. Had a similar sheepish experience with fix-a-flat, with the addition of a threat against my person if I ever used the stuff again. Well, that's why I asked.

3.) Oh it sure is. I just ordered the stainless set for my carb intake boots from Mr. Robert Barr along with those o-rings. I'd put black hex nuts on there already, but the gleam of stainless, well... you said it. Meanwhile, I stopped at Ace on the way home and picked these up. Shiny. I didn't get washers - is that alright?

4.) I'll check that out next oil change. Meanwhile I'm glad about the o-ring. When I changed the oil last time it seemed fine, so I didn't worry about not having a new one. Guess now I'll hang on to the one I bought.

No gasket delivery yet - hopefully tomorrow.

[TheCafeKid]

Roberts set will come with washers, and i would suggest using them. His set also comes with healthy dose of what appears to be antisieze in the bag...very nice touch.

[Roostabunny]

Roberts set will come with washers, and i would suggest using them. His set also comes with healthy dose of what appears to be antisieze in the bag...very nice touch.

Oh yah - those I'll use the ones that come with Robert's kit for sure.

What about for the cam chain tensioner? There's no washers on those stock mounting bolts, they just look like they have slightly bigger heads than the stainless bolts I bought to replace them.

[Roostabunny]

Foot Powder

A GSR member emailed me for details on the "foot powder" procedure. Not much too it, really, although I probably should have explained the context of my comment.

From reading around the forum about oil leaks, there seems to be a standard procedure for finding them.

1. scrub the engine clean of all oil and grime
2. start her up and watch (like a hawk) for oil to see where it starts

Some folks have added a helpful step in the middle which is to dust the engine with talc or baby powder. This helps two ways. First, it sort of flattens the visual field by hiding the natural color variations of the engine block. Imagine a hunter in camo standing in the woods. Now imagine if you spray painted all the trees white. This is especially helpful if you keep up with your oil changes, as nice clear oil is harder to see (even on a clean engine) than black sludgy stuff. The second way that it helps is that the powder absorbs the oil a little, slowing the drip process and providing an easier way to trace the leak. Leaks (with clean oil, anyway) show up as caramel-colored "blooms" in the field of white powder.

Finally, to advance the "baby powder" method one more step, somebody figured out that a spray powder (such as foot power or certain deoderants) goes on quicker and more evenly than baby powder. Probably easier to get it in between cooling fins and such, too. More expensive, but very fast and easy. Due to cost, I think I'll actually try regular baby powder next time, but you can see from my pics that the foot spray goes on pretty even.

Meanwhile, folks like you and I get to stand on the shoulders of all these clever folks and find our oil leaks the quick way.

[Roostabunny]

No soup for you!

Darn - no gaskets today. They were sent Priority Mail on Friday, so I was sure they'd be here by today...

Oh well, I decided to get started without them and not rush myself. I'm actually kind of glad - one of my ignition cover screws is being stubborn, and it'll give me time to borrow an impact driver along with the feeler gauges. Sprayed some PB Blaster on it in the meantime. Also, my new half moons shipped from BikeBandit today so I'll probably wait till they arrive (hopefully by Friday) to finish up and try out Steve's valve shim calculating spreadsheet.

The breather cover was really gunked up, so I'm sure that gasket was leaking, too, oozing down the whole back side of the block. I got the covers off and found the offending section of the old gasket. A small crack, but enough.

I considered pulling the airbox and carbs off while I'm waiting for the gasket so I can get a better look at the cam chain tensioner leak (and install my spiffy new intake boot o-rings and stainless bolts from Robert Barr), but I'm nervous to have more than one thing apart at once with as little space as I have to work.

[chef1366]

Replace all those phillip heads with allen heads.

[Roostabunny]

Here's the source of the leak - crack allowed gasket to shift.

Sorry about the picture quality. Used my phone because I've misplaced my camera.

[Roostabunny]

Still no soup for you!

Drat, no Real gasket yet!

I'm holding out hope that it'll arrive by Saturday afternoon otherwise I'm driving instead of riding again on Monday.

It was sent USPS priority mail from TN on Monday.

In better news, my oil filter from Bikebandit (and half-moons) and my carb boot o-rings and stainless bolts from Mr. Robert Barr did arrive, so at least I've got something to distract me while waiting for the mailman!