Leaking oil: big deal, or small deal?

[Syscrush]

Hey all. On a recent trip I found that I was down a bit of oil, and some hunting around under the bike found that it was leaking from somewhere near the countershaft area. From the reading that I have done, this could be the countershaft seal, an o-ring on a nearby bolt, or the starter o-ring.

How do I isolate the cause? I was thinking I would pull the sprocket cover, clean up the area as well as I can with some kind of solvent, and then do a careful visual inspection after riding. But if someone has a better and/or more foolproof approach to suggest, I'd love to hear it.

I don't know if it matters, but here's how the area looks now:



Thanks for any pointers.

[NobleHops]

I'd do just what you suggest, remove what I could, clean it up, and see where it's coming from. The output shaft seal is a known culprit in this area and there are procedures for extracting and replacing it if you search for it. I've also heard of folks 'fixing' seal leaks like this by adding a small amount of kerosene to the motor oil, thereby swelling the seal. The guy that bought my GT750 did this to my old bike when he discovered that issue, although I never heard how long it lasted.

N.

[EMS]

It could also be the seal on the shifter shaft. Cleaning all up and checking for the origin is the best low effort solution.

[NobleHops]

Also - I have heard of folks spraying powder deodorant in a cleaned-up area to help detect leaks. I tried it with limited success on a gas tank leak I was chasing - might work better here. Clean it up thoroughly (with something compatible with the rubber seals), spray the powder deodorant to cover the area with white powder, fire it up to make some oil pressure and watch and see what happens.

Please close the loop and let us know what you learn.

N.

[daves79x]

You photo shows perhaps something more sinister. Your cases have been welded/repaired from some past incident, likely chain related from the looks of it. I'd strongly suspect that's where it's leaking. In any case, the other's advice is good for finding it.

Dave

[bikeymikey748]

Phil, head on over to Canadian Tire ( or any other auto parts store ). Grab a can of motor shampoo, avoid the foaming kind.
Follow the directions. I've found a warm motor, as opposed to a hot one, gets better results with the shampoo. Remove the sprocket cover to make certain you get all the residual oil off the cases.
You'll be needing a dye kit to add to the oil too. A few ounces is all it takes. The tough part is buying/renting/borrowing/stealing a U.V. light to check for the leak. I've a small one that looks like a flashlight. Most garages should have one, I imagine they would be more than willing to check out your six while shining a light on the plot. A few bucks slipped their way should seal the deal.
After the shampoo,and dye are done, and leaving the sprocket cover off ( no bell-bottoms! ), go for a ride.Try to stop at 10 min. intervals at first. This will give you an idea of the amount of oil you're losing over what interval of time. If there isn't any accumulation, increase the intervals slightly. You should be able to notice the leak easily enough. Checking with a U.V. light will confirm, with accuracy, the source(s).
After that, hopefully, it will be a simple enough matter to correct the leak.....fingers crossed

[Syscrush]

Thanks to all for the advice & pointers. I'll definitely update as we work to get this sorted out.

Special thanks to Dave for pointing out the signs that there's been welding done on the case. Obviously I'd rather have pristine cases, but given that the work has been done, I'm better off knowing about it.

[Syscrush]

Well, the mystery deepens. Today I pulled that cover and gave that area it a thorough clean, along with the whole rest of the engine (using a few shots of brake cleaner in strategic areas, engine cleaner from a spray bottle, and then the pressure washer in a coin-op car wash). Then I proceeded to ride ~120km, with one stop about halfway through.

At the halfway stop and again when I got home, I crawled around under the bike looking for any sign of weeping or leaking oil, and I found nothing anywhere. Dry as a bone all over.

This makes me suspect that the oil shown in the picture at the start of this thread was some combination of solvent and lube flung from the chain. I know that my mechanic cleaned & lubed the chain before I took delivery in Mar, but I didn't give it or that part of the engine a careful look at the time. The return leg of my recent Montreal trip was almost 7 hours riding in heavy rain, plus another hour+ of breaks where the bike sat in the rain. There's no sign of lube left on it now (it is an O-ring chain so I don't stress too much about lubing the outside).

But there's no doubt that oil poured into the engine is disappearing to somewhere. By my understanding, the 3 most likely culprits would be:

1. The oil breather puking out excessive oil.
2. Leaking past the valve stem seals and/or rings, resulting in burning & expulsion out the exhaust.
3. Boiled/burned off when caught in stop & go traffic.

For the time being, I'm going to keep an eye on the level to come up with an estimate of the rate of loss, and keep checking for signs of leaking on the engine. I'll update as more info comes in.

[Rick Pope]

Phil,

Keep in mind that a little oil consumption is not necessarily a bad thing. The top ring gets lubed by whatever oil the "oil ring" leaves behind. If the oil ring does too good a job, it's actually harder on the top rings, and cylinder.

That said, modern engines do a pretty good job of living on very little oil. Advances in metallurgy have brought us far.

The only time I've used much oil was when running pretty hard, keeping the engine in the higher revs.

[NobleHops]

It doesn't look like chain lube or even gear oil to me Phil. Could be weeping out that welded area over time. There is a locktite product specifically made for sealing porosity in cast metal - this came up on a BMW board I used to frequent. I'll go dig it up if it turns out that's the culprit. I like Mike's plan with the leak detection stuff best - then you'll know where its coming from if the oil reappears. My '80 uses oil too - it smokes a bit on startup and then seems to seal up once it warms up. I suspect the old valve seals too, and I have a set of the Viton ones in hand for Some Day, but I know damn well if I pop the head I'm gonna do the cam chain tensioners and maybe install those 79 cams I have and oh how about some Oldham couplers and and and, so I have done nothing but add oil now and then.

Oil is much cheaper

N.

[daves79x]

Phil:

I can tell you that 7 hours of riding in the rain caused some oil consumption. The engine could never get to operating temperature in the rain to seal the rings well. Same thing happens in very cool weather or at high altitudes. But since you need a baseline for what your normal consumption is, hard to say just how much more it may have used in the rain.

Normal (if there is such a thing) oil consumption for a healthy CBX engine should be no more than a quart per 1000 miles. Most of mine have never used a quart in 1500-2000 miles. See if your base consumption, in normal running and temperatures, is in that range.

Dave

[bikeymikey748]

Mystery indeed. Looking at the photo it appears to be an 'active' leak. The area looks wet and the amount of oil seems to be enough to wash any accumulation of dust/dirt away with it as it runs down the cases.
Typically, if it had been an accumulation of chain lube, the deposits would have been more dry and thicker in nature. Riding in wet conditions would have left deposits that the hot cases would have cooked into a grey residue....unless an 'active' oil leak was present.
The head scratcher is that 120km.,after the area had been cleaned, should have been ample mileage to show some sort of leak???
I thought that Dave's, keen, observation regarding the welded case repair would turn out to be the 'smoking gun', but apparently not.
Is your oil level correct, not overfilled? The routing of the airbox's drain, is it in close proximity to the area, is the hose damaged? If your are getting an abundance of oil vapor in the box, too much for the motor to draw off, that might be an issue. It would be one that, by nature, would take a bit longer to present, over something like a leaking countershaft seal, for instance. Have a look in the airbox, how are things in there, dry?
Dumb, last question, your filler cap, tight...'O' ring in good condition? Accumulation in that area?

[Goss]

A quart is close to 1 litre which I believe is the quantity required to take the oil level from the low to high on the dipstick.

Riding around in 20 degrees centigrade 70f and not going over 6,000 rpm for much of the time would give me 1,500+ miles per quart (litre). I don't ride like that normally so would expect around 1,000 miles per quart this is based on 10/40 in in cool temps, if the outside temp is 30/90f and above I would run on 20/50 which gives me the same consumption.

Running your CBX in the heat on the lower permissible oil level will make the remaining oil work harder so I top up every 500 miles, when it is on the lower mark it is 25% down on lubricant and cooling .

As Nils said, oil is cheap.

Regards

Goss

[EMS]

The welding on the cases are a problem only if the break reached into the inside of the cases. After taking a closer look, I would think that this did not happen.
As far as this possibly being chain lube is concerned, it all depends what chain lube was used. Some of the stuff is pretty liquid and when it gets hot, it really becomes runny. Mind you, by design, it is supposed to creep into the tight spaces of the chain links.

To diagnose leaking valve guide seals, it is good to check whether the engine smokes out of the exhaust right after start-up. The oil has a tendency to accumulate in the cylinders aftert he engine is stopped. At re-start it burns up in a larger amount and smokes through the exhaust. Soemtimes only on one side.

[Syscrush]

Well, it definitely isn't fling from the chain. I pulled the chain cover today, and there was no oil on the inside.