400 EX just quit

[250RGUY]

i was riding in some mudd and water and my ex quit on the other side. I got it started again and it ran for a while but would just quit running out of know where.. I can here valves or a piston or something slapping. Now the damn thing wont even roll over. Whats wrong with it?

[4TraxRider]

Sounds like you have some serious water damage. If it's not turning over at all and the battery is charged, you have an engine seizure, or the cylinder is full of water and water doesn't compress. You have to at least pull the plug and see if there's water in it. If it still doesn't crank over, you had a engine seizure. Take it to the dealership. Good luck.

[nismo]

when i ride ont he powerlines and go through big puddles my motor wants to shut down but i just get on the gas and it starts to run fine again. this isnt the same is it? is it hurting the engine?:confused: :confused: :confused: :confused: :confused:

[250RGUY]

We jump started it today and it ran a bit then shut down. It misses when its running then you hear a clunking sound and it locks up. Now the battery just clicks and it doesn't start or roll over at all. I am going to drain it out tomorrow but I wasn't in enough water to even talk about so I dont think thats whats wrong.

[toby400ex]

if it starts then quits, its prolly something electrical or water in the carb.

[Big - D Racing]

check your plug

[Giz400ex]

Originally posted by Big - D Racing
check your plug That would be the first I would do and change:D

[JOEX]

Originally posted by Giz400ex
That would be the first I would do and change:D
Me too :macho
May have just got some water around the spark plug boot.
Another thing to check is the battery connections. They are known to come loose.
If the oil is milky you have other more serious problems.

Joe

[250RGUY]

I drained all the gas out of the carb and let it fill back up with fresh. Didn't help. Its not the plug. This thing will not even roll over now. The batter just makes a clicking sound. I jump started it and it ran a bit then a crappy valve slapping sound or piston then shuts off. Now it wont even pop start or roll over. It wouldn't start for a day while it was all muddy, I washed it off and sprayed the battery with water like crazy and I hit the electric start and it fired up. That worked 1 time. Now its completly dead. I haven't got a clue what could cause it to run like this, its not blown up or it would never run.

[JOEX]

I'm not so good at trouble shooting but it sure sounds like an electrical problem. They can be a nightmare to figure out.
Get the battery charged properly or replaced and go from there.
How are you sure it isn't the plug? Even though it may "look" ok it could be cracked and shorting out.
Can you swap the CDI box with a buddy?
Check all the electrical connections for cleanliness, dryness and tightness.
I'm sure it's something simple, just time consuming to find.

Joe

[drip]

It sounds like your battery may need replaced or charged and you might as well change the plug and see what happens after you try these two suggestions. Did you check to see if you had water in your airbox?

I submerged my 400ex yesterday. The creek was deeper than I thought. It came up to my handlebars. I am not happy because I changed my oil last weekend and now I had to change it again because i got some water in the motor. it was a mess.

[250RGUY]

Tomorrow I'm going to check the plug, change the oil. Already checked the air box, I wasn't even that deep into the mudd and water to get the air box wet. I cant swap cdi box's with a buddy cause everyone went to freaken suzuki. My battery isn't working right I know that. I didn't mess with it enough to cause it to be dead so it might just be junk. Tomorrow I will know more. Thanks for all the idea's though it should help me to focus on a few things instead of going in blind. Thanx...

[speedy]

your ground wire has came loose maybe(wire that hooks to the frame
:macho

[cals400ex]

what scares me is that you say when it does run it makes a bad ticking noise coming from the valves or piston. you may have an electrical problem too but it sounds like you may have an internal problem too. i would get a new plug and battery and see what happens. also, change the oil.

[250RGUY]

I checked the plug its fine. The battery is charged. I drained the oil and found some large metal chunks. There is also metal flakes in the filter. It will run but not good. I think the timing tensioner may have broken and the chain is slappin around in there. As soon as I can find a repair manual for it i'm going to tear it apart and see whats up. Those metal flakes have me worried but the large chunks worry me more. Hopefully its just the chain.

[250RGUY]

Any idea's now guys? Thanx

[Bud88]

you may have broke a ring on the piston ive had it happened to me before and it was causing compression to go into my crank case and blowing oil out of my blow buy what a mess butt if you broke bad enough it may just not have enough of compression to start at all

[AtvMxRider]

Originally posted by 250RGUY
I checked the plug its fine. The battery is charged. I drained the oil and found some large metal chunks. There is also metal flakes in the filter. It will run but not good. I think the timing tensioner may have broken and the chain is slappin around in there. As soon as I can find a repair manual for it i'm going to tear it apart and see whats up. Those metal flakes have me worried but the large chunks worry me more. Hopefully its just the chain.


If you found metal chunks why in the hell are you still running it:huh ? Well the more you run it the more damage you are doing to it. Just pull it apart and find out what the problem is.

[250RGUY]

Haha...I didn't run it after I found the metal chunks man. When I emptyed that oil pan and saw all that crap I put it on the trailor and stuck it in the garage. Just waiting on a manual now.

[250RGUY]

The motor is out of the frame and up on the bench. Now for the hard part, someone with zero knowledge of the 4 stroke engine tearing one down for the first time. This 400 may be headed for the junk yard after this...lol...I hope its the timing chain and not something more serious.

[JustRace]

Doesn't take a lot of mud to ruin a motor. Once it clogs up the oil cooler, then the fins on the motor it makes one hell of a insulator. Once the motor gets to hot because of the mud it seizes up. I am willing to bet that is what you did, seized the motor, atleast the rings, then broke them loose and tore the inside of your motor up. That make sence to anyone else. I think the first mistake you made was trying to force a motor to run that didn't want to run.

[250RGUY]

Seems like I misled you guys some how. When I broke down in the middle of a coal strip mine, yes I tried to get it running again. When I got it home and drained the oil, no I never ran it again.

The motor is not blown up, I know that without even lookin in there cause it has compression. I was in deep water but not oil cooler deep. It has to be the chain tensioner on the timing chain. I'll let ya'll know tonight after I tear it apart.

Just thinking out loud here,

If there wasnt any water or mud in the air box or filter (do you run a lid?) then most likely the water had little to do with the damage, but if it did get into the filter-carb-cylinder etc then it could cause the rings to blow out, broken rod, crank and even bend valves and timing chain failures as well.

Since you are saying that there wasnt any water in the oil and just chunks of aluminum then most likely the rings are intact otherwise water would have gotten past them (at least most times).

If you did take on water and the engine tried to compress it in the comp stroke allmost all of the above things could have been damaged. So I would deff take some time and read over the manual to get used to it and then start tearing into the engine.

This is a pretty simple engine and working on it is not that diffilcult so dont fear it but do take your time and do it right.

If you can tell how often the "clunk" happens in relation to the strokes of the engine you can eliminate many of the potenial problems. This isnt easy but can save some time.

Remember that there are a lot of poeple here who have been into these engines before (I can take this thing from fully assembled with plastics down to the crank in under 30 min when rushed now) and will be able to help you out if you run into trouble or questions etc. Your in good hands :)

[250RGUY]

I took the lid off this baby and took the chain tensioner plug out. This is the steps the manual said to follow. Then it says to turn the timing chain counter clockwise and take two bolts out of the sprocket. The chain will not rotate counter clockwise. I looked in the tensioner hole and there is scratches up and down the side where metal has been flaked off but nothing as big as some of the chunks i've found. It said to never turn the chain clockwise so I just left the thing sit. Seriously thinkin about sending it in to get fixed. There was no head gasket on this thing when I took it apart , but there wasn't water in it when I drained the oil.

The guy at the shop said if I tear it apart first and then take it to him he's gonna charge me double. He likes to tear it down so he knows how it goes back together. So if I cant figure it out tonight I'm just going to pay to have it fixed and maybe throw a 440 kit on it. Who knows.

Check your pm box

[nakomis0]

So you couldn't see what broke and caused the damage?

The only part the mud and water probably had in causing this damage was over revving with not much resistance at the wheels. Thats how bearings inside the cause get wasted real quick. Then them pieces of metal take out the rest of your engine, its real bad.

So anybody who hears clunking in there engine, dont run the motor or only as little as possible.

The motor is actually simple to tear into. It can save a $50 fix from becoming a $2000 fix. If its the lower half of your motor thats a pain, .. splitting the case gears, bearings, crank, rod, lots of parts.. etc., etc. Good luck.

[AtvMxRider]

Originally posted by 250RGUY
. There was no head gasket on this thing when I took it apart , but there wasn't water in it when I drained the oil.




Why would there be water in it?

[250RGUY]

I dont know it quit running for the first time when I went through a deep mud puddle. So I just figured I got water in it some how. I've been too busy to mess with it plus I have no clue what I'm doing so it just sits in the garage torn apart at the moment.

[250RGUY]

Tore it down to the piston yesterday. Everything looks good. There is play in it that will need fixed but its not the reason it wont run. Probably going to have to put it back together and ship it off somewhere. I'm in over my head.

[250RGUY]

I think the crank bearings went bad. Have to split the motor I guess. I would say this thing will never be put back together after I'm done slinging parts around I wont know where they all go. lol..... Might be partin this baby out some day.