GSX600F Smoking...suspecting valve oil leak

[Katfan]

KR's,

Good news! Thank the advise of several of you the problem was identified: The excessive exhaust smoke was caused by the oil-soaked muffler (after the engine flooded with fuel while in storage.) For the benefit of others who have a similar issue here is a recap:

Problem: exhaust starts smoking (blue) gradually more and more as engine warms up.
- GSX600F, 2003. Crankcase flooded with fuel while 1.5 yr in a shed.
- Flood caused by leaky float needle valve. Cleaned, adjusted.
- Oil changed 3 times to rinse the crank case from fuel residue.
- Cleaned carb and adjusted float, pilot screw.
- Started engine again and removed the muffler when the smoke started. There was virtually no visible smoke leaving the header assembly.
- Will burn out remaining oil in muffler while riding a few miles on higher RPM.

Thanks everyone who chipped in. Rob

Original posting:

"Hi Fellow KR's.

Could you please help me figure out why my 600 exhaust starts smoking oil as it warms up?
The engine is very responsive to the throttle. When in idle there is no trace of smoke, in the exhaust but after a minute or so the smoke is more and more visible. When I pull the throttle the smoke just shoots out like a chimney so I need to turn it off.

I don't think the piston rings are the problem. My compression test showed around 160PSI on all 4 cylinders. I suspect it is the valve seals are leaking through oil.

Initially the crankcase flooded with gas due to stuck float valve. I changed oil, spark plugs, cleaned carb and adjusted floats.

The bike is 2003 model with 20,000 miles and it is in a decent shape. I would love to fix it up nicely and I am thankful for any advice.

Cheers,"

Rob....

[92xjunker]

Valve guides....does the oil smell like fuel and the oil level at the full make when the bike is sitting in the riding position?

[Katfan]

The oil smells normal. I confirmed that there is no longer any fuel leaking into through the float vales. I used a bottle for fuel gravity feed instead of the tank. I marked the level and it did not change overnight. The oil level has been near the F mark at the inspection glass and that has not changed.

My only other guess was the contaminated air filter (K&L). It had the oily gas mixture still on it after the fuel flood issue. (I.e. the air box was filled with the oil backing up.) The filter was not dusty or dirty though. I cleaned it anyway with K&L "juice."

If I take off the cylinder head how do i check valve guides and seals? Or should I just simply replace it?

Thank you. R.

[92xjunker]

You can remove the head, remove the rocker assembly, remove the valve springs. If the the valve falls out easily or the shaft wobbles while in place the seal and valve guides are worn. Now you have three options, have the head rebuilt, rebuild it yourself, the guides are pressed in, or buy a good used head. Also look at the head gasket and seals, it could of blown out.

[ygolohcysp]

Did the bike smoke like that before it flooded? If not, I would maybe try changing the oil one more time first.

When the bike flooded, was it started or turned over at all? As in, did the fuel in the oil circulate in the motor? If so, there is oil in places like the cooler which don't drain when you change the oil. If there is still fuel in there, it could just be leaking through because it's thinner than oil.

Also, what color is the smoke? White, blue, black? Does it eventually quit, or once it warms up and starts smoking, does it continue until it's shut off?

[Katfan]

Ygolohcysp - Thanks for checking in and the good questions. Here is what I got:
1. Did the bike smoke like that before it flooded? => I don't know. I got it like that from previous owner.
2. When the bike flooded, was it started or turned over at all? => I did not realize at first that it was flooded (rookie mistake I know). Engine turned over but did not start. Than after carb cleaning it started for 5-10 seconds but stalled. I changed the oil.
3. As in, did the fuel in the oil circulate in the motor? => I am sure the mixture is all over in every little passage way.
4. Also, what color is the smoke? White, blue, black? => Definitely blue and smells like burned oil.
5. Does it eventually quit, or once it warms up and starts smoking, does it continue until it's shut off? => I did not run long enough to tell. I ran it on the stand for 2 minutes at a time tops. After a smooth start no visible smoke out of the exhaust. After 30 seconds idling slowly starts smoking and it increases. It becomes dramatic when I pull the throttle. Literally a jet of smoke shoots out of the exhaust pipe 10' long and creates a huge plume. I did not want to risk overheating due to lack of airflow. The engine seemed to heat up very fast.

I also noticed that while it was smoking, a few drops of black oil was leaking through under the exhaust pipe joint clamp. I thought it might be old oil residue in the pipe so I took it apart but the exhaust was pretty ok. There was only a thin layer of thin soot on the inside of the exhaust pipe. I guess the fresh oil from the engine leaking through.

Thanks for your help. R

[ygolohcysp]

Okay, so blue smoke and smell, it's definitely oil.

You have good compression in all 4 cylinders.

You said it has 20,000 miles. That's not a lot. These motors are known for going up to and over 100,000 with proper maintenance. I know that's an unknown since you just bought it used, but I'd think something major would've had to happen for the valve guides to be bad, and you'd have other symptoms.

One more question. Is this fuel that was in the bike when you bought it? That might be a stupid question if it had leaked all the fuel through the carbs. Just wondering if the PO might have put something in the fuel for storage, or even added 2 stroke oil to it or something.

If the cost of cheap oil isn't an issue, I would maybe try changing the oil one more time and see if that changes anything. At the very least, pull the dipstick and see if the oil feels thinner than any leftover new oil you still have.

Otherwise, I would pull the fairings and tank, and check the spark plugs. Are they coated with carbon from oil getting into the chamber and burning? Could at least help pinpoint if it's that, or if there's oil leaking down an exhaust valve and not burning in the combustion chamber. Could also help determine particular cylinders to look at.

After that, maybe pull the valve cover and see if you visually inspect how things look from the top side. I can't remember if you'd be able to see the valve seals through the springs.

[maniac1886]

If I was a betting man, I'd put money on leaky valve seals.

[92xjunker]

Me too.....

[maniac1886]

Which sucks.... Lol

[Katfan]

Guys, I appreciate all your advice. At this point I am determined to take a look under the valve cover. I hope I get lucky and its only thinned oil as ygolo suggested, but if I have to rebuild the valves I am okay with that too. So I will pull the cover and order whatever parts I need. I rather do it once and right and ride with a peace of mind that is fixed. BTW I saw through the spark plug hole that the piston top is full with carbon build up. I will deal with it after I got the bike running decently.

O.K. so I have the work cut out for me to keep me busy for a while. I will tackle in two weeks and of course will report back in on the progress.

Thanks again and be safe on the road.
Cheers,
Rob....

[bbstacker]

Before you tear anything down, run it longer. Could be the muffler packing is soaked with oil/gas mix and is burning out. Happened to me this spring on a 2000 Kat 600 I rescued(stored 5 years). Smoked so bad a neighbor called the fire department. Oil filled airbox, 2 gallons gas/oil in crankcase, same as yours. It'll burn out.

[Katfan]

Hm, okay. It is worth the try. Thanks.

[92xjunker]

Easy test, pull a muffler off and run it.

[Katfan]

Smoking caused by oil-soaked muffler

Before you tear anything down, run it longer. Could be the muffler packing is soaked with oil/gas mix and is burning out. Happened to me this spring on a 2000 Kat 600 I rescued(stored 5 years). Smoked so bad a neighbor called the fire department. Oil filled airbox, 2 gallons gas/oil in crankcase, same as yours. It'll burn out.

BBStacker. You were right on. The thick exhaust smoke was caused by the oil soaked muffler burning out. Following 92xjunker's suggestion I removed the muffler when the engine was warm and the muffler started puffing out the ridiculously thick blue smoke. Virtually no visible smoke came out of the header assembly. So I just have to ride it a bit. Thanks for the advise. You saved me a lot of work.
Cheers ...

I followed the suggestion and took off the valve cover. Everything looked great, like the bike just came out of the factory. I could not see much of the valve guides but it probably would not matter much without taking them out i.e. drop the engine, remove the head to check the valves. I figured I put the cover back and give your muffler removal test a try.
It worked!! Thanks again. R