Okay, this is fricken rediculous.

[FoxRacing81]

I have my 400ex at my friends dads shop.
One day when I was riding it, I heard a noise and then my quad just shut off. I went to crank it back over, and I heard the starter, but no motor.

So, he ripped it apart and found that the lifter tensioner was bad. He replaced it. Nothing changed. He ripped the whole motor apart and checked the crank. The crank was in perfect shape. He thought maybe the timing chain in the bottom end skipped a tooth. He tried that. Put ti back together. Nothing happened. He is now ripping it apart for the 3rd time to try and figure out what it is. He also checked the keyway to see if the pin sheared, but it didn't. So now he is clueless. He is gonna check the camshaft but he's running out of ideas.

Anyone?
Please help me.

MXEX


EDIT: BTW, He checked the valves and they were fine, and the piston was fine.

[mojoe2878]

what kind of noise did it make when it died out?
what all mods do you have?
what part are you talkin about when you say a lifter tensioner?
i assume he's allready checked for spark, compression and all the basics before he tore it down?
have you checked all the electrical stuff?
is the motor even turning over or is the starter just spinning?

[speedy400]

Are you sure your starter is engaging? it is suppose push out when you hit the starter, take yours off and make sure its working correctly maybe? just an idea. also if your sure thats working, take the side covor off and take out the spark plug so you dont have compression, and put it in gear, and see if you can spin the motor by hand..-darren

[FoxRacing81]

I don't know what kind of noise it made becuase I wasn't expecting it to die so I didn't really pay attention. I think I heard like a clunk.

Yeah he checked for compression and spark and gas.

I'm not sure what all mods are done.

I kno its bored and stroked (i dunno what size it is though), it has a hotcam stage two, its ported and polished, has nickel coated rockers, and thats all I know. Plus a K&N and white brothers r4.

like I said, its at my friends dads shop, not here, so I can't check anything.

And the starter is just spinning, the motor isn't cranking over at all.

BTW, It can't be the starter gears because if it was, it wouldn't just cause my motor to all of a sudden shutoff.

[speedy400]

Well It would have to be either a bearing went out or gears went out, or bolth. Maybe you accedentally bumped the starter botton with you were riding and didnt notice it and sheared the starter gear. Or a lower end bearing went out, killed the engine, then the starter enguaged but the gear wouldnt move and sheared something so the starter gear is stock in place but the starter shaft is just spinning. This is a tough problem you have, dont worry though, I've had redicules problems such as, who knew I would have to fully dissassemble my FCR carb and fully clean it 3 TIMES before it would work!? That problem alone took 1 1/2 months to find out. good luck, dont give up-darren

[chucked]

wtf? how can you check for compression and spark when the engine wont even turn over?

[nosliw]

Originally posted by chucked
wtf? how can you check for compression and spark when the engine wont even turn over?

lmao thinking the exact same thing....

[FoxRacing81]

idk, I wasn't thinking. Couldn't you check the spark though? My warrior had a problem one time where the sprocket and cam we're spinning freely so the motor wasn't turning over but I still had spark.

[BSTURDIVANT]

Starter clutch, if just spinning!

[SoUpX]

maybe your kill switch is over...... make sure it's in the middle ;) j/k but seriously check it out, I've seen people accidently hitting it and flippin out because their new quad wont start... check spark plug, wires hoses whatever, then 20mins later they check the kill switch.... I'm sure it's not that though, just thought i'd share that cause it always makes me laugh...

[toby400ex]

PLEASE tell me you have tried to bump start it! If the starter will spin freely, and the motor does nothing something is obviously wrong between the engine and starter.:huh

[FoxRacing81]

I checked the off/on switch.
If its the starter gears, then why would my lifter tensioner have gone bad?

I hope most of you know what the lifter tensioner is. It's the tensioner that holds the rubber piece tesnioned against the timing chain.

I'm thinking now either a snapped connecting rod or somethin like that.

[sickmojave]

Originally posted by MX610EX
He ripped the whole motor apart and checked the crank. The crank was in perfect shape.

and now you think it's the rod???? Dude what your saying makes no sense.:(

[chucked]

Originally posted by MX610EX
I checked the off/on switch.
If its the starter gears, then why would my lifter tensioner have gone bad?

I hope most of you know what the lifter tensioner is. It's the tensioner that holds the rubber piece tesnioned against the timing chain.

I'm thinking now either a snapped connecting rod or somethin like that.

thats the cam chain tensioner. WTF!!! if the engine isnt even cranking over!!!!!!! omg yo, whoever is working on your stuff does NOT know what they are doing!

[chucked]

ok lets get this straight...

When you say

"And the starter is just spinning, the motor isn't cranking over at all."

you mean the starter is just spinning and the motor isnt cranking over at all right?

[FoxRacing81]

Umm...no...the Rod isn't the crank. The rod bolts to the crank. He could have easily not noticed the rod when checking the crank...I think.....I'm not sure I don't know much about motors I am simply giving information that my dad has told to me and my friends dad who is working on my quad has told to me. So yeah.

[hondardr4life]

LOL, I am 1 of those people who accidentlly hit the kill switch and then flipped out. Anyways, I doubt it is a bad connector rod, I think it would have made a really load noise if it snapped. Do what they said and try pushing it down a hill and dumping ou the clutch. That shoud help you determine what it is. If it does start, or you hear the motor trying to turn over, then it is probablly a starter problem and you would just have to buy a new starter. If that isnt the problem, then I have absolutly no clue:confused:

[FoxRacing81]

IDK Man its hard to explain.

The reason I call it the lifter tensioner is because if you go on albaaction.com, click on find stock parts fast, then click on honda atvs, 2000 400ex, and timing assembly w/ cam chain or something, they call it the lifter tensioner.


Now, the closest thing I can tell you, is if you have ever heard a raptor try to start whenever its one way bearing is out. You hear the starter spinning, but it wont engage and spin over the motor.
That's what it sounds like when I hit the starter button.

[FoxRacing81]

Now, correct me if I am wrong, but if a starter gear went out, it wouldn't just cause my motor to all of a sudden shut off, would it?

[hondardr4life]

Does someone wanna explain to me what "its one way bearing" is??? And yes I have heard a raptor with a bad starter try to start. All the starter does is spin and nothing happens with the motor.

[sickmojave]

Originally posted by MX610EX
Umm...no...the Rod isn't the crank. The rod bolts to the crank. He could have easily not noticed the rod when checking the crank...I think.....I'm not sure I don't know much about motors I am simply giving information that my dad has told to me and my friends dad who is working on my quad has told to me. So yeah.

Excuse me but you said he tore the whole motor down and checked the crank.you could not do this and not notice a broken rod. sounds to me like you need to load it up and take it to someone that knows what they are doing. :ermm:

[FoxRacing81]

I didn't mean rip the whole motor down. It was an exaggeration. He ripped it down to check the crank, he didn't tear the whole thing down to nuts and bolts.

[4StrokinJay]

Guys...I think we're over thinking this...If the starter turns and the motor doesn't....try checking the spark gap on the vehicle you used to tow the honda with...


It seems silly that you are having the motor tore down over and over to check the crank, rod and your "tensioner" thingy when the problem at hand doesn't even point you in that direction.:confused:

[chucked]

Originally posted by 4StrokinJay
Guys...I think we're over thinking this...If the starter turns and the motor doesn't....try checking the spark gap on the vehicle you used to tow the honda with...


It seems silly that you are having the motor tore down over and over to check the crank, rod and your "tensioner" thingy when the problem at hand doesn't even point you in that direction.:confused:

like my dad always said, if it doesnt work, change the spark plug


Raptors have a one way bearing on the starter gear, they fail pretty often, I have never had my 400ex starting system apart so I dont know how it works. Something may have gotten caught from the starter onto the flywheel and shut the motor off. Im gonna take a look to see how it works.

[mojoe2878]

Originally posted by hondardr4life
Does someone wanna explain to me what "its one way bearing" is??? And yes I have heard a raptor with a bad starter try to start. All the starter does is spin and nothing happens with the motor.
i think he is talkin about the starter clutch.
i figured in the first post when he said lifter tensioner that he was talkin about the cam chain tensioner but i wasnt sure, ive never heard it called a lifter tensioner before.
why dont you take a 18mm socket and put it on the flywheel nut and turn the motor over by hand and see if everything is moving freely and check to see if you piston is coming all the way up flush with the top of the cylinder.
it sounds kinda like the rivets that hold the flywheel to the starter gear and crank gear have sheared, not the key but the rivets. i have worked on a motorcycle with similar problems and it was the flywheel rivets had all sheard off.

[AtvMxRider]

Originally posted by MX610EX
Umm...no...the Rod isn't the crank. The rod bolts to the crank. He could have easily not noticed the rod when checking the crank...I think.....I'm not sure I don't know much about motors I am simply giving information that my dad has told to me and my friends dad who is working on my quad has told to me. So yeah.


1st off the rod doesn't bolt to the crank. Man you need to take that quad to somebody that knows what they are doing cause this guy sure in the hell doesn't:rolleyes:

[AtvMxRider]

Originally posted by MX610EX
I didn't mean rip the whole motor down. It was an exaggeration. He ripped it down to check the crank, he didn't tear the whole thing down to nuts and bolts.


Ok how in the hell do you not tear the whole motor down to get to the crank:confused:

[xrxmxcx]

this happened to my warrior...check the starter clutch (orwhatev, you call it) my starter would engage but the teeth in the gear were strippid out on the recieving end of it because i hit the starter while riding...and is the starter engages at the wrong time it can stop your engine..it happened to mine

[BSTURDIVANT]

Just reading between the lines- one possibality- starter turns, guy took out sight plug on flywheel side and noticed flywheel turning. He is probably right about broken rod-they are bad about breaking rods after mods! Would explain "pop" and shutdown!

[Aceman]

This is just an idea....but I think mofoe is on the right track. Say you shear the flywheel rivets, your flywheel stops spinning and therefore stops charging. It would kill the quad. That would explain the pop sound and his quad dying. Then when he went to crank it over, the flywheel would just spin with the starter because it's no longer riveted to the hub and so it wouldn't roll the motor over. Well that's my best guess. A little difficult to make an accurate diagnosis when this kid's posts are all over the place.

[FoxRacing81]

This is exactly why I don't like exriders for quad problem questions. Because the only thing that happens is I get b!tched out if I don't know every single thing about my motor. I'm sorry im not a master mechanic. I'm giving as much as information as I know. Don't get all b!tchy because I don't have all the information straight.


And btw, if the rod doesn't bolt to the crank, where does it bolt?

[chucked]

Originally posted by Aceman
This is just an idea....but I think mofoe is on the right track. Say you shear the flywheel rivets, your flywheel stops spinning and therefore stops charging. It would kill the quad. That would explain the pop sound and his quad dying. Then when he went to crank it over, the flywheel would just spin with the starter because it's no longer riveted to the hub and so it wouldn't roll the motor over. Well that's my best guess. A little difficult to make an accurate diagnosis when this kid's posts are all over the place.


um if the flywheel stops turning, the bike does too, period

[chucked]

Originally posted by MX610EX
This is exactly why I don't like exriders for quad problem questions. Because the only thing that happens is I get b!tched out if I don't know every single thing about my motor. I'm sorry im not a master mechanic. I'm giving as much as information as I know. Don't get all b!tchy because I don't have all the information straight.


And btw, if the rod doesn't bolt to the crank, where does it bolt?

uh no, you are just posting some b.s, you cant check compression or spark when the motor is not spinning, the only reason it is bad for information because the people asking are saying wrong things.

it doesnt bolt, it is pressed into place

[FoxRacing81]

OMG, BIG FRICKEN DIFFERENCE!!!!!!! He sounded like he was trying to tell me it connected to the handlebars.

Yeah, I'm posting BS. Yeah ok....I'm not allowed to make any mistakes with you people. Man....IDK what to think. Some of you guys seem like your trying to turn yourself into bad*****es. If someone don't post something exactly right, lets b!tch them out and tell them how stupid and wrong they are instead of telling them "No, it can't work like that" or something...jesus..

[Aceman]

Originally posted by chucked
um if the flywheel stops turning, the bike does too, period

I understand that. All I was saying was that the flywheel itself is riveted to the gear that's attached to it, isn't it? I don't have a 400 so I can't check it out myself. But I doubt the flywheel is one solid piece of metal. It most likely is a few different parts riveted together.

[AtvMxRider]

Originally posted by MX610EX
OMG, BIG FRICKEN DIFFERENCE!!!!!!! He sounded like he was trying to tell me it connected to the handlebars.




No I am trying to tell you that you and your so called mechanic are idiots:rolleyes:

[Aceman]

Originally posted by MX610EX
OMG, BIG FRICKEN DIFFERENCE!!!!!!! He sounded like he was trying to tell me it connected to the handlebars.

Yeah, I'm posting BS. Yeah ok....I'm not allowed to make any mistakes with you people. Man....IDK what to think. Some of you guys seem like your trying to turn yourself into bad*****es. If someone don't post something exactly right, lets b!tch them out and tell them how stupid and wrong they are instead of telling them "No, it can't work like that" or something...jesus..

Chill....we can't diagnose the problem properly if you can't describe the problem properly. Simple as that. You want to do a better job describing, then go to www.servicehonda.com and start posting some schematics pointing out the different parts you've checked so all of us are on the same page figuring out this problem. The sooner we understand what your saying, the faster we can figure it out and the sooner you'll be riding.

[mojoe2878]

Originally posted by chucked
um if the flywheel stops turning, the bike does too, period
i thought the whole problem was that the bike stop turning over, or the engine did anyway.

[chucked]

Originally posted by Aceman
I understand that. All I was saying was that the flywheel itself is riveted to the gear that's attached to it, isn't it? I don't have a 400 so I can't check it out myself. But I doubt the flywheel is one solid piece of metal. It most likely is a few different parts riveted together.

what im saying it, when it becomes disconnected while the motor is running, its gonna hit something and cause havok on the motor.

[Aceman]

Originally posted by chucked
what im saying it, when it becomes disconnected while the motor is running, its gonna hit something and cause havok on the motor.

Possibly, but it has the stator inside of it holding it in place. His quad died immediately, so it might not of had a chance to break loose and tear the motor up.

[chucked]

Originally posted by Aceman
Possibly, but it has the stator inside of it holding it in place. His quad died immediately, so it might not of had a chance to break loose and tear the motor up.

maybe thats what the noise was? It would be a very possible cause, it sheared off, got caught up on the inside of the motor and stalled it out and now the starter doesnt touch it.

[Aceman]

Now if MX610EX would tear his case off and take a look we would know if were on the right track.;)

[chucked]

Originally posted by Aceman
Now if MX610EX would tear his case off and take a look we would know if were on the right track.;)

hell probably end up taking the swing arm off then asking us where the flywheel is :devil:

[Aceman]

Lmao......that would make for one long night.:blah:

[mattonln]

alright, lets stop ragging on the unknowledgeable.... MX610EX, first find a hill and push your quad down it and dump the clutch... if the motor turns over, then you've narrowed it down alot! if not then your friends dad most likely doesn't have the skill to fix it without getting himself into a huge project. like many have said, worse case scenario, take it to your honda dealer and say "this piece of **** won't start..." good luck...

[YZ400EX]

Do not take the quad and push it anywhere..Just take off the big flat head screw on the left hand side of the engine by where your feet would be, grab a socket (17mm I believe) that fits the bolt you will find under the screw and turn it left like you wanted to loosen it. If the motor turns over and you can tell that everything inside is moving (piston, valves,etc...) and doesnt bind at all, more than likely there is nothing wrong with the internals and like alot of others here have said it could be that the "star" type screws that hold the flywheel to the gear/s that run the starter have sheared off and would cause the gear to spin freely and not turn the engine over..Also I may be wrong here (never pulled apart that part of my 400 yet) but I believe that it has a 1 way bearing on the back of the flywheel like other Hondas I have worked on. This may have gone out too. I dont think this would cause any motor noise and make it die(you never know though..anything can happen), but it would explain why the engine wont turn over when hitting the starter...You really just need to try and turn the engine over with a socket and ratchet..If it turns over with no binding I would really check out all the starting components before tearing anything else down on the Quad..

[FoxRacing81]

Okay, we all good now? All still friends and stuff? I have not had all the information given to me correctly. I now have the main scoop.


Okay, the problem was that a tooth broke off the gear that the timing chain spins on in the bottom end. If he would set the chain to a different point on the gear, the quad would fire right up and run until it got to the broken off tooth then it would skip time and shutoff. So all I need is a new gear and I'm in business.

Thank you all for this experience. I actually learned some stuff in this situation. Thank you. I will continue to use these forums as long as too many people don't think I'm an idiot.

[YZ400EX]

No problem man..Everyone has to start somewhere!! Good luck on fixing it..