Oil pouring out left exhaust header pipe!

[write2paul90277]

Hi guys, long time, no contact (my fault)

While re-restoring my 76 RE5, I was shocked to see a half pint of fresh motor oil come pouring out of the left muffler head pipe when I removed it for cleaning.

The bike was running fine when I put it in storage 2 to 3 years ago. After carefully using the kick starter to confirm that the seals were not frozen, I put in a new battery, changed the engine oil, sprayed some starting fluid into the plug hole and fired it up for about 5 seconds.

Encouraged that the bike still started, I proceeded with my detailing, which included pulling the exhaust system.
That's when I discovered FRESH motor oil pouring out of the head pipe -- only on the left side!

(By the way, the bike was on it’s center stand the whole time, not leaning on the sidestand.)

Any ideas of what might have happened?

Baffled,

Paul Wilcox
Redondo Beach, CA

[bdalameda]

Perhaps the oil injection check valve stuck open and over time oil fed into the carb and flowed into the motor. Never heard of this happening and not even sure it could happen - other than this it would have to be a side seal but there really should not be enough oil with the engine stopped to leak through that much. Since you have already started it I would get it going with some clean fuel and run it a bit and see if everything is OK. Check that the injection oil line check valve is working and the injection oil pump is bled and working. I would also run some premix until you are sure things are OK.

Dan

[tom93gts]

I am having a hard time imagining where that much oil in the exhaust would come from aside from putting some oil in the spark plug hole to prep the bike for storage.

If it were an oil control ring that would have leaked only when running and caused lots of smoke with maybe a little residual oil in the chamber and out the exhaust when shut down.

If it were from the OMP it would have had to pass through the OMP, fill the carb with oil and drain from there into the combustion chamber. I wouldn't say that is impossible, but I would be at least a little surprised if oil would run right through the stationary OMP. Is your oil reservoir under the seat empty? I guess that is the more likely scenario aside from somebody sneaking in and dumping oil into your spark plug hole without telling you

[write2paul90277]

So far, it's still a mystery.

The bike wasn't burning oil when it last ran (a few years ago). Could I have blown a seal just by cranking the engine over and letting it run (on starter fluid) for 2 to 3 seconds?

The reservoir tank is still full, so it's hard to imagine that being the source of the oil in the header pipe. For that matter, the carb had no fuel in it and the OMP wasn't spinning long enough to push much oil through).

The only thing I can think of is that when I changed the oil in the sump, I MAY have overfilled it, BUT a quick look at the dipstick shows that the oil is right in the middle of the recommended fill zone.

Hopefully more will be revealed!

Thanks for your help thus far.

Paul

[tom93gts]

If there was no oil in there before you started the engine, the only way it could get that much in it so quickly is if a rotor face was broken. So that is a possibility. If you pull the spark plug and turn over the motor with the starter do you hear 3 even pulses? If compression is lost through a big enough hole on the rotor you will hear it.

[goandy]

Vaguely possible but I've never seen a broken or holed rotor. Those things are a pretty decent chunk of cast iron!

I'd imagine that it's just your oil control ring rubbers are a bit cactus and the oil from inside the rotor has seeped past then out the exhaust port to the exhaust. If it's okay most of the time, just leave it- or if you're brave you could strip the proper unit and replace the rubber rings and whatever else you find!

[tom93gts]

True that rotors don't break too often, I have only seen it if a bolt or something similar was dropped into the engine. That was in Mazda rotaries, not sure how the Suzuki rotor compares to that. I just can't imagine that much oil coming in through any of the seals, even if you completely removed all the internal oil seals it would be difficult to get that much into the motor after only a couple seconds running. No matter what it is though, I am pretty sure the proper unit will have to be replaced/rebuilt.

[goandy]

Just an example. One of my cars doesn't lack a single drop of oil normally but if you leave it for more than 4-5 days a huge pool of oil appears underneath it. Turns out it comes from the rear main seal which appears to dry out, shrink and allow oil to pass in large quantities. No idea where the oil comes from either! If this bike was left for 2-3 years and maybe even cranked over every no and then, its entirely feasible its oil from inside the rotor. If its running well, not smoking too much and not consuming too much oil, then it may be best to just ignore it!

[tom93gts]

Very true, I perhaps incorrectly understood that there was no oil in exhaust prior to starting the engine.