2018 GP water in oil

[5valve]

When used 60hr bike was purchased, it had a slight splooge leak at cylinder to head contact, front LHS. Gearbox oil was replaced, since old was emulsified.

Removed head, to find 1.9mm inner oring, instead of 1.78.
Guy said that head was never removed from new. Debatable.
Installed original size orings, without greasing them, but after 1 hr, water broke into gearbox again.

Second head removal...when I undid one of head bolts slightly, pressure hiss and a bit of water came through.

I stripped top end, new piston, gaskets, orings, new water pump seal. Also lowered head for squish and did compression adjustment, so head is 100% true.
Inspected head and cylinder, no visual cracks, no wear on parts, WP shaft like new.

First startup with renewed top end, instant emulsion party.

Since all the obvious are not to blame, I'll need to dig deeper.

Are there any known issues for those models that were happening?

Possible culprit:
- cylinder top uneven, resurfacing would make oring grooves shallower.
- porous crankcase or bad gasket mid engine
- hidden cylinder crack

For squish fine tuning I used two 0.1mm athena gaskets, they are plastic transparent - check pic, and put the original steel 0.5mm on top of them.

All mating surfaces were thorougly cleaned, degreased.

 

[blitz11]

I bought a KTM exc 200 from a friend for my daughter about 12 years ago(!).

He had the cylinder re-plated and installed a new piston for us.

My daughter rode it on its inaugural ride.

It looked like a steam train when she rode it - steam followed her wherever she went.

Not good.

Pulled head/cylinder. I made a rig out of 1/4" thick AL and a schraeder valve so that i could pressurize the cooling passages connected to the exhaust chamber.

The cleaning process prior to replating must have created a small hole 'cause the bubbles were fast and furious. I used JB weld as a sealant in the offending cooling passage, and it's been good for a dozen years.

You might have to do a similar process. Casting porosity isn't that unusual.

 

[gasgasman]

Leaking head seals won't cause water in the oil.

More than likely, you have a bad water pump seal.

 

[gasser]

I once put together a gasser engine that had been setting in pieces for serveral years. Long story short I missed reinstalling the o ring that goes behind the water pump seal. That o ring works in conjunction with the seal and without it the engine sucked oil from the right side crankcase.

 

[5valve]

Blizt11, where did you mount alu plate, top of cylinder or base or else? Not sure if mine is "burning" water, but it seems to be pressurized or leaked into gearbox.

Gasgasman, on previus gg300, I wrongly used larger head oring. Exactly 1.9 instead 1.78. When torqued, it got stuck between head/cylinder mating surfaces and probably created hairline compression leak into cylinder cooling passage, increasing pressure in cooling system and forcing coolant to move through path of least resistance, through water pump seal and into crankcases, mixing it with oil.
Replacing head oring with correct one instantly removed leak, and old water pump seals functioned years after.
But as a precaution, I did replace a new set of water pump seals on the new bike, so new seals got a blowby.

Gasser, will look into oring on the water pump, dont recall it, only rubber inner seal, white plastic washer and spring pressurized seal are in the set. I'm not burning gearbox oil, but rather leaking or pressurizing antifreeze into gearbox oil.

 

[blitz11]

I used a thin piece of aluminum (license plate) with the head o-rings to seal the top of the cylinder. by sealing the grooves, i could just pressurize the cooling passages going by the exhaust port.

I took some scrap 1/4" AL and some gasket material to block off the lower cooling passages which served the exhaust port, and drilled, tapped, and installed a Schraeder valve to pressurize the system.

I then dunked the pressurized system into a bucket of water so that i could find the bubbles coming through the casting wall.

Once i knew where the hole was, i just covered the inside of the cooling passage with JB weld.

JB weld probably doesn't transfer heat as well as AL, but it's been fine since.

 

[5valve]

I'm not a native english speaker, but as I understand, you blocked water passages on cylinder top and bottom, installed valve, pressurized and dumped into bucket.

So actually passages are not all interconnected, so you can block individual cells.

I might need to block them all, since pressure is also bursting into coolant, which is then pressurized into gearbox, mixing with oil. Only place to allow that (deformities aside) is water pump, which I renewed, and through valve rod hole.

From memory, while I was polishing the exhaust port and valve, did spot a crack, that didnt want to buff out completely, located on the lower side of the port, but it seemed too far out to matter. It goes deeper then in picture.

What was the exact location of your leak?

 

[blitz11]

I'm not a native english speaker, but as I understand, you blocked water passages on cylinder top and bottom, installed valve, pressurized and dumped into bucket.

So actually passages are not all interconnected, so you can block individual cells.

I might need to block them all, since pressure is also bursting into coolant, which is then pressurized into gearbox, mixing with oil. Only place to allow that (deformities aside) is water pump, which I renewed, and through valve rod hole.

From memory, while I was polishing the exhaust port and valve, did spot a crack, that didnt want to buff out completely, located on the lower side of the port, but it seemed too far out to matter. It goes deeper then in picture.

What was the exact location of your leak?

Your English is very good. Your interpretation of what I wrote is correct.

The KTM had 2 cooling passages, one on each side of the exhaust port/power valve chamber. The casting was porous, leaking into the exhaust stream. I could isolate, mostly because i knew that the leak was entering the exhaust stream.

I think that in your case, I am not sure that coolant into your exhaust port would lead to water in the transmission oil. My thought would be that if you have oil contaminated by the coolant, that water would have to travel through the right-side power valve chamber and into the oil.

You could check that pretty easily by running the bike with the power valve chamber cover off. If you see coolant, you have the problem.

Could you have a bad water pump seal? I know that you replaced it, but it is possible that the new one was damaged? Maybe the o-ring?

Good luck.

 

[5valve]

When purchased the bike, got two sets of water pump seals. I also inspected shaft, and it is spotless.

I ran the bike the day before yesterday after rebuild, and checked the oil window and saw this. That instantly led me to believe, that water came in.
https://www.youtube.com/watch?v=HxeAjK_D2-w

But today, I checked after bike was cooled, and it looked like this...so damn, for now it seems it is ok. Oil level is full.

Redid the same process today, run and stall and it was the same again. I'm using diesel automotive 10W-40 oil, just to clean previous emulsified gearbox.

My previous bike never had such violent oil mesh.

So far so good, but it still might mix water on an actual ride, but hope not and that WP seal, head job did the job.

 

[blitz11]

That oil looks clean, but your video does look like a water emulsion.

Strange.

Was the level that high before? if so, could water come out of the emulsion, and the oil is sitting on top of the water?

I am sort of at a loss at this point.

good luck. nice sleuthing.

 

[5valve]

Will drain and inspect after longer ride. If water still persists after few cleanup drains, then a cyl pressure test. Helpful thanx.