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'04 KTM 125sx leaking coolant onto piston

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hey guys this is my first "thread" and im brand new to the forum, but the situation is im DESPERATE to figure out whats going on with my motor, somehow coolant is getting into the cylinder and onto the piston. its causing my radiators to boil over in about 3 mins and is filling my pipe and silencer up with coolant as well, because shoots out the exhaust port. i don't think this matters but i just switched to engine ice after a BRAND NEW rebuild. i never started it up prior to these problems, so im thinking the guy who worked on my dirt bike might have messed something up. ive done everything i know to do and have inspected the cylinder walls, gaskets, o-rings, and everything looked good when we were rebuilding it but somehow there's coolant getting to the piston. the guy who rebuilt it thinks there's a crack in the cylinder but ive inspected every inch of it without as much as the slightest hairline fracture. however since we broke it down to inspect the cylinder and piston weve discovered that the cylinder wall is now scared close the the top of the cylinder wall directly above the exhaust port, the guy who rebuilt it claims that it was there before from the pevious 2-ring cylinder, and the stress from the coolant and excess heat from the 1-ring weisco pro-lite piston caused it to heat up and show up more. anyways seems like the base gaskets head gaskets and everything in place but still cant figure out where coolant was coming from, i know this is alot to take in and theres alot more to know so ask me what you want to know and ill try to fill in

PLEASE HELP!!!!!!!!!!!!!!!![/left]

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Welcome!

Few things,

I wouldn't run anything but an original 2 ring KTM piston or the Vertex 2 ring piston. This whole 1 ring thing, its for people who don't mind replacing their piston every weekend and need the absolute most performance out of a single race.

In terms of your cooling problem, It could be something like a cracked cylinder where the porting is, so its hard to see. You could easily pour water into the cooling area of the cylinder and see if it leaks out. Other wise, its gotta be a bad seal or poor mating surfaces between the components.

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okaty thanks never thought of the water thing, and yeah tell me about it i ordered the top end kit off motosport thinking it was the 2-ring weisco prolite piston but apparently its a 1-ring... why would they do that i thought thats what the gp model was for?

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I think your engine builder is making things up. If any scarring was there, it's his job to make you aware of it and decide if you want to run it or not. My guess is the head o ring got pinched at assembly and that's why it leaked. For the few $$ I'd replace it and see where you end up.

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well after closer examination theres engine ice in the bottom end, i drained the oil thinking that that would drain all the liquids but there was no engine ice so im thinking im wrong, but i can tell its down there because when i rotate the crank theres blue liquid around it, so any ideas on getting it out? id try flipping the bike upside down to drain it but its raining outside, and im thinking the engine ice got down there because the piston has so much play from side to side theres space for it to get through. but i did notice the coolant ladder runs through the bottom end. anyways you all know more than i do

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spizz5: (I think your engine builder is making things up)

yeah im pretty sure of that too i should done it myself to begin with but the guy acted like he knew what he was doing and i ride with him and hes been riding for a long time so i thought what the hell why not. big mistake apparently

and btw, after i took off the 2 head o-rings i realized they were never coated with vaseline recommended via instructions from cometic.

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The engine oil you drained is for the trans only and never touches the crank. Flip it over ASAP and get it dried out and lubed up before it starts rusting.

Why did you rebuild to start with? Was it just due or did the engine fail?

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well to be honest i guess you could say both, you see i bought it from a second owner, and its a 2004, and since i broke it down and looked at the piston it looks like its the original piston... that being said my bike sucked dirt due to a worn out un-seated filter on the track my last ride and to my opinion caused the rings to wear out, it didnt explode but it lost almost all compression, so i shut it off on the spot and began the breakdown like 3 days later, or the terrible "mechanic" did anyways, lots of dirt in the engine got cleaned out

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Ok well the point is it wasn't leaking water prior to tear down, so that pretty much eliminates the cracked cylinder theory. I still say the head o ring got pinched at assembly and let coolant into the combustion chamber. I would also guess that coolant washed any oil off the piston and cylinder and caused all the scoring you now have.

How long have you ran the motor with this problem?

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i ran it once fresh after the rebuild for maybe 10-15 mins because guy told me to seat the rings, so he had mi rev it about 1/2-3/4 throttle at an dead stand still in N. i thought that wasnt right at all. then he went and got another inner head o-ring after it shot coolant out the overflow valve the first time because he swore he put in a head gasket that was too big on there whenever it said on the package 01-04 KTM head gasket or o-ring or somethin. after he showed up with an identical head o-ring that fit like the one before, we drained the coolant re-assembled it and after about 3-4 mins of revving did the exact same thing as before, shot coolant out the overflow valve. but when i took off the head o-rings after all that happend (by myself this time) i realized he never applied seal grease or vaseline like the instructions called for and the inner o-ring had been smashed in some spots it sorta looked like.

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WOW, just WOW.

Lemme tell you somethin', I'm a 4 stroke roadracer engine builder. I've been in some pretty complex motors, but never in a 2 stroke one. When I bought my lil 125SX and had to do a top end, I immediately fell in love. I didn't read the stinkin' manual, I didn't talk to anyone, I literally figured it out as I went along and ya know what, they are THAT simple.

So with that said, anyone with any mechanical understanding that can't put the motor together properly needs to have his/her head examined. That lil 125 lump, is so straight forward, I would beg to say its "bulletproof"'. Though don't tell that to your mechanic, he/she is libel to take it the wrong way! LOL :lol:

Ohh, so yea your problem.

Well, if coolant is dumping in from the head whilst the motor is stopped, it will find its way down through the intake and exhaust porting and into/onto the crank and into the exhaust. I don't think your bottom end has a problem, its just a gasket issue I feel.

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I KNOW!

you wouldnt believe it! i had this guy rebuild my engine figuring it was a complex task, but next thing you know he jacks it up and here i am 3 weeks later tearing the engine down myself only to find how simple it would have been just to do it myself!

but, its over and gone now,so, the fact is i gotta get my cylinder rebuilt, someone mentioned a company called millinium, but all i know is itd be around $240 as apposed to the herrindously overpriced $400 KTM oem cylinder new. And on top of that theyre supposed to match the cylinder to your exact piston, what do you think?

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What I think is you need to have someone with a trained eye look your cylinder over and verify the plating is damaged before sending it to Millenium. The scoring on your cylinder may very well be aluminum deposits from the piston that can be cleaned up without needing a replate.

As for the Lack of lube on the o ring, I have assembled with and without it. I wouldn't say it caused the failure, but it sure didn't help either.

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but, its over and gone now,so, the fact is i gotta get my cylinder rebuilt, someone mentioned a company called millinium, but all i know is itd be around $240 as apposed to the herrindously overpriced $400 KTM oem cylinder new. And on top of that theyre supposed to match the cylinder to your exact piston, what do you think?

Yea Millennium is the best place, though I would contact Andrew @ http://www.cookseycrank.com/ and see if he can help you out, you might be able to save some money going through him. Also, you still didn't exactly find where it was leaking did you? I'm very concerned about that because as I said earlier, I'm very surprised it leaked since these motors are so easy to put together. So maybe something IS wrong... did you try my test mentioned earlier?

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well i know for sure the cylinder is scared, i can run my finger over the wall and its a pretty deep spot directly above the exhaust port, and you can see where it wore through the... nikasil?... lining, i think thats what its called. and yeah i tryed your test and didnt find any leaks so i guess it HAS to be the o-rings, and on top of that the cylinder top has some imperfections that might not let the seal seat perfect, i think its from the dumb $%# who tried to port and polish the cylinder messed it up too, one of the "mechanics" friends. anyways why would cooksey crank help me out on a refurbished cylinder i thought he just did cranks? if i do go with millinium im doing there cylinder exchange program.

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anyways why would cooksey crank help me out on a refurbished cylinder i thought he just did cranks? if i do go with millinium im doing there cylinder exchange program.

Call him, he is a motor builder, expert on 2 strokes and has good connections for parts. Millennium won't exchange your cylinder, they will only fix it. I just went through this with them and they don't have KTM parts sitting around sadly.

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What I think is you need to have someone with a trained eye look your cylinder over and verify the plating is damaged before sending it to Millenium. The scoring on your cylinder may very well be aluminum deposits from the piston that can be cleaned up without needing a replate.

As for the Lack of lube on the o ring, I have assembled with and without it. I wouldn't say it caused the failure, but it sure didn't help either.

well i know for sure the cylinder is scared, i can run my finger over the wall and its a pretty deep spot directly above the exhaust port, and you can see where it wore through the... nikasil?... lining, i think thats what its called. and yeah i tryed your test and didnt find any leaks so i guess it HAS to be the o-rings, and on top of that the cylinder top has some imperfections that might not let the seal seat perfect, i think its from the dumb $%# who tried to port and polish the cylinder messed it up too, one of the "mechanics" friends. anyways why would cooksey crank help me out on a refurbished cylinder i thought he just did cranks? if i do go with millinium im doing there cylinder exchange program.

Well that was pertinent information much earlier in this thread. Therefore if you had some moron that thought he could do some inexperienced port work take a Dremel to your head/cylinder and improve it, I don't care how easy tye1138 tells you it is to assemble, he had no business holding wrenches in his hands. I can certainly see now how an o ring got improperly installed or a non flat gasket surface resulted. Can you post pics of the head and cylinder gasket "imperfections"?

And again I suggest letting somebody look that plating over, often times aluminum deposits from a seizure look and feel like indentations but when a hone is ran through they are gone.

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Well that was pertinent information much earlier in this thread. Therefore if you had some moron that thought he could do some inexperienced port work take a Dremel to your head/cylinder and improve it, I don't care how easy tye1138 tells you it is to assemble, he had no business holding wrenches in his hands. I can certainly see now how an o ring got improperly installed or a non flat gasket surface resulted. Can you post pics of the head and cylinder gasket "imperfections"?

And again I suggest letting somebody look that plating over, often times aluminum deposits from a seizure look and feel like indentations but when a hone is ran through they are gone.

Yes, I absolutely agree. Which is why I mentioned Andrew. :lol:

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okay well uploaded cylinder pics on same photobucket album:

( http://s1199.photobucket.com/albums/aa470/bajabeast2008/?action=view&current=IMG_01101.jpg )

btw i remembered that the same dumb @$$ that worked on it also said he flushed the "old coolant" out by putting tap water in the radiators and ran it for the first run on the piston or the "break in" secession i told you about earlier, whenever it first leaked coolant, but i remembered the coolant was actually water, then the second startup or break in secession we switched to EngineIce, both times liquid ended up in combustion chamber.

http://www.thumpertalk.com/forum/images/smilies/bonk.gif

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