2014 kx250f tipped over in a mud hole

Hi there, im desperate... I was riding the trails a couple of days ago and my bike tipped over in a larger muddy puddle of water, ran for about 5 seconds then I picked it up and it stalled upright... kicked her over with no problems and it ran for another 30 minutes getting out of the trails. there is now a knock in the engine when it idles. you cant hear it at higher rpm's but its very clear that its there at any other time. the bike runs and starts with no problems there is just that knocking.

 Im just wondering if anyone has any experience with this, do I need to replace the crank (maybe a bent rod)?

Im pretty positive water got into the engine, when I changed the oil it was a very dirty brown. Also is there a possibility there is a tip over sensor on this bike? 

2014kx250f 

Thanks in advance.. 

Edited by jessicamarie253

A bike running when tipped over and underwater is bad news,never try to start it  when you pick it back up,google or search on here how to de-water a bike and you need to go through that and get all water out of the bike before trying to start it again,once it is started then head back to the cars and change the oil and keep changing it till it comes out clean,the longer water stays in there the worse it is,it will wreck the coatings on bearings inside the engine,from the sounds of it you may have had water in the cylinder whilst still running-only way to find out is to pull the motor down and see what damage there is

Okay, I will be pulling it apart tonight. This happened on Sunday and ever since then I have been changing the oil constantly. 

The weird thing is that it runs fine other than the knock i can hear.. no backfiring or anything. 

yea not sure about how to do a 4 stroke. I saw were dirtrider actually sunk a 2 stroke in a pool. Pulled it out and went thru it and it ran good

I can assure you there is no Tip-over sensor on the bike....I sunk a KLX300 to the point where you could not kick it over if you wanted it was filled with water... I drained it down changed the oil 5 or 6 times and all was good. But I'm afaid the difference here is you ran it with water in the engine. Water and Oil do not mix so as it was circulating there was times that the moving parts where subject to only water as lubricant not oil....

Water mixed in with oil whilst not good for it still means you can ride the bike back,the bigger problem is getting water in the cylinder whilst still running either before you can turn the bike off or trying to start it up-water doesn't compress like the fuel and air mixture and something will bend as I suspect the noise will be in your case.Have you had a look yet to see what is knocking?

There is a vehicle down sensor on your bike.  As for the water infiltration, you changed the oil, so good.  Whether there was any damage is questionable.  The safe bet would be to evaluate the knocking you hear.  It might help to post a video.  

 

You may want to pull the head and cylinder just to evaluate the rod.  While you are at it you could replace the piston and shim the valves as maintenance.  

Being that it started right up and ran I highly doubt anything is wrong. Is it possible that noise was there before but you didn't notice until you were looking for a problem. Idk how you could bend a rod or anything else from dumping your bike. Who hasn't done that a ton. If water got into your oil it would look milky white. In the northwest during the winter my bike is constantly in mud puddles. Thinking you need to tear your whole bike apart cause you tipped over in a mud puddle is "Internet over thinking " If your really concerned about the knock take it by a shop and let a mechanic listen to it.

Being that it started right up and ran I highly doubt anything is wrong. Is it possible that noise was there before but you didn't notice until you were looking for a problem. Idk how you could bend a rod or anything else from dumping your bike. Who hasn't done that a ton. If water got into your oil it would look milky white. In the northwest during the winter my bike is constantly in mud puddles. Thinking you need to tear your whole bike apart cause you tipped over in a mud puddle is "Internet over thinking " If your really concerned about the knock take it by a shop and let a mechanic listen to it.

If your bike goes under water then water can and does get sucked in through the air filter through the carby and into the cylinder,it can also come through the exhaust pipe and into the head-what do you think happens to any amount of water that makes it inside the cylinder,it doesn't just compress and burn away,I like my bike and if it goes under water and I hear a knocking noise afterwards then I certainly won't hope for the best I would rather pull the cylinder head off and check.You are correct alot of people dump their bikes into water,most stall when doing so and some will stay running,most get away with just water in the oil and easily fixed if you change out the oil,some are not so lucky.

Edited by ozglenn

Sounds like a bad bearing. Not good news.

Ok, so we started the tear down by checking the valve clearance - all good. Timing also good, pulled the head off, valves good. Valve guides are good. Then pulled the cylinder, found no problems with the piston and cylinder, some scoring on the wrist pin and top of connecting rod, we were not satisfied that was the source of the knock...

(Curious to what might have caused that scratching) wondered if the under piston spray nozzle was plugged? Proceeded to remove the engine cover on the clutch side, found the oil seal for the crankshaft oil feed to be ripped open, which would cause low oil pressure(it wasn't just ripped on the sealing surface, it looked like it was damaged during assembly or somehow over pressured) and although some questions were answered, we now had another though, what else might have blown?

Crankcase has been split, may have found the problem...

The cylindrical sump filter is coated (completely plugged) with what looks like mud. Would this create low oil supply/pressure to the rest of the engine and therefore create a knocking sound? Any thoughts?

If this is the problem, a new oil seal, a new wrist pin, and a new sump filter and I'm on my merry way.

Crank or rod bearing seem like should be the culprit

If you got mud into the motor then safest is to rebuild bottom end with new crank bearings and make sure the big end bearing and conrod is still ok.

 

just a small amount of mud will damage the bearings.   

This was the crankcase filter.

1431008223842.jpg

So, I just wanted to keep those following this kept up to speed.

My dad is extremely confident it's not the crank bearings because there was no play in them, but the knock still exists and we have went through the entire bike. Split the case and all, now what?!?! What else could it be :(

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