Bizarre Oil Leak From Exhaust Port? Need Help.

Bizarre Oil Leak From Exhaust Port? SOLVED

Hi guys, I have an 86 VFR700 and I've been trying to track down this small oil leak on the front right hand side of my engine. It only leaks when I'm riding it and the air flowing in this area blows the oil around making it hard to find the source. I'm always spraying this area with carb cleaner and wiping it down in hopes of finding the source.

I suspected the valve cover so I pulled both of them, adjusted the valves and then used a smear of RTV silicone on the gasket to seal them back up. I also added a bit of silicone to both sides of the rubber bolt seals. Not my source of leaking.

I sprayed some carb cleaner into the exit of the spark plug drain hole and got it nice and clean then plugged it up with a paper towel. After a ride it was nice and dry. It's still leaking from somewhere.

I got lucky yesterday as the oil patch was very small and localized, but there is nothing there for oil to leak from except the exhaust port itself. I included a good picture (I found on Ebay) of the area the oil was in. I checked the exhaust bolts and was able to tighten them a little more, like 1/4 turn. I can't see or hear any exhaust leak from this area.

Is it possible for oil to be dripping down from an exhaust valve and being blown out the top part of the exhaust seal? It seems bizarre to me. Maybe I should just pull the exhaust pipe off, replace the seal and see what happens?

 

Check the plugs. If the one with the leaky exhaust is fouled or a different color from the rest. If you are getting oil in that cylinder it could be guides or rings or a fouled plug. If all that checks out do a compression and leak down test. After that just relax and keep an eye on it. Hope its something simple.

Bill

 

The plugs are fine. I haven't done a compression test as the bike has lots of power. Like warp speed!

 

When you go to replace the exhaust gasket check inside the pipe. If it has signs of oil in it it has to be coming through the cylinder. If no oil signs then maybe a leak saturated the gasket at one point and now its just coming out as you ride. I say replace the gasket and recheck periodically. If there are signs of oil in the pipe you can do the other stuff.

 

If you have a valve guide leaking you should be getting some smoke out the exhaust. This is the most likely cause but the other option would be a crack in the head. It sounds like you have cleaned the area pretty good and I'm sure you looked at it closely so something like a crack would have been evident. If it was a crack, there is a chance that it only opens up when the heads are hot.

 

I don't see any head crack and it doesn't smoke.

So you guys think it's actually possible the oil could be coming from the exhaust port? I've never seen that happen and was just guessing.

It's possible the PO jacked up the bike from the exhaust pipes which I think would try and open the gap on the top of the exhaust gaskets.

I should be able to get some new gaskets tomorrow and then take a better look.

 

There are only four options here. 1 is the valve cover and the most likely. 2 is the gasket between the valley of the two cylinders......wildly beyond the thoughts of reality, but hell stranger things have happened...3 is the cylinder is pukeing oil but with no smoke I say less than no odds. 4 is casting flaw in the head......uber rare but have seen it on other brands.

 

I took it out for a ride and the leak is gone! Giving the exhaust bolts a little extra tightening must have done the trick.

What a strange leak. Granted it was a small one. An hour long ride would only produce about 5-6 drops of oil, but the wind would smear it all over the front of the engine. After a couple of rides it would get all over the inside of the fairings, etc... So I'm glad I got it sorted. I think my bike is officially "leak free". :thumbsup:

Anyway, This thread is now marked solved. (Dang, it's still leaking! )

 

Congratulations!!!!!!!

 

You might want to invest in some new valve head bolt washers, those tend to loose their thickness and rubberyness after being squashed one time too many.

 

My little leak keeps coming back. I pulled that pipe off, cleaned the mating surfaces really well, painted the pipe and installed a new copper ring gasket, but it still has a tiny leak near the top once it heats up.

Maybe the heat is causing a gap to open up?
Do you think some high temp exhaust sealant would hold up to the heat?

BTW, the old copper gasket was flattened uniformly around like it should have been. There was no signs of oil inside the pipe or exhaust port.

 

One easy way to locate niggling engine oil leaks is to pour a small bottle of fluorescent oil dye into the engine oil and cycle it through Jason.



Then use a small black-light leak finder kit like this one to locate the source of the oil leak. You should be able to find these items at any auto parts store.

If you suspect that you have a leaky exhaust valve seal,than you'll be able to verify that for certain by dye checking it.

 

Why does it stay sealed when I tighten everything and go for that first ride. After the second ride, it's leaking again?

Are the OEM copper seals just crap? Is there a special technique for torquing the exhaust pipe flanges?

 

Are you absolutely sure the bike isn't using oil? Has anyone followed you on a long ride and looked for smoke? It might only smoke under hard acceleration or on the overun.
If it is leaking around the exhaust port gasket then the oil must be coming past the valve guides??

 

That gasket is designed to contain exhaust gasses not oil. What you are experiencing is a symptom of another issue which must be sorted out as the other members have already stated. Change you valve guide seals and more than likely the issue will not come back.

 

Valve cover or exhaust valve guide. If it's heat related, then you can probably get it to happen by warming the bike up at idle until the cooling fan comes on. You may not need the load from riding it (although the header won't be nearly as hot that way). I second the use of the dye to find it. pull the fairings off, idle it, and keep checking with the light every few minutes as it warms up. Maybe heat cycle it a few times in the garage.

 

Update, it's still leaking. I did a few things to make sure the valvecover is not leaking. It's not.

I sealed up the exhaust really well, it's not leaking either.

I was going to get some dye, but it's $8. Seems a waste of money, so I cleaned the area real well with carb cleaner and clean paper towels and squirted some talc powder around the whole area. I wasn't sure what I was seeing the first time around so I cleaned it again just to confirm.

It's leaking from a seam in the casting! (Nope, I spoke too soon)

How would you fix this? I'm going to try a dab of silicone. If it doesn't work, maybe some paint will seal it. The hard part is stopping the oil from seeping through until they have time to properly cure. Any other ideas?

 

wow, that sucks... hairline crack, huh? I'd put a new (well, used), head on it. Repairing a crack like that in an aluminum casting is going to be hard. And if that's cracked, the next question really is WHY? did it overheat? was it in an accident, etc. There could be more going on.

 

Did you know those are rubber bonded to metal? I think it's the heat that causes them to get hard.

Anyway, instead of going to the dealer and spending 5 bucks or more each I got some rubber grommets from the local hardware store with the correct inner diameter and then used my grinder to shave down the outer diameter and thickness so that they squish down the valve cover real tight and lock down. Works great, especially if you want to replace all 8. $40 gets reduced to about $5. :biggrin:

Dude, don't freak me out.

The engine seems fine. Doesn't use oil, runs great, pulls like a raped ape. I'm just going to seal it cheaply and not worry about it.

 

Just saying, cracks like that shouldn't just happen...