Big Prob!!Gas,Spark,Compression..Wont Start??

[StupidHurts]

02 400ex
All Factory..
Its getting gas
has lots of Spark
and it has enough compression to run

It wont even pop nothing at all..
It seems like it has no spark but i checked it 4 billion times and it does..
The gap is right and its a new plug
The gap on the valves are good as well
the carb is almost spotless and its getting gas
When i take the plug out after trying to start it its soaked with gas..
So that leaves me at square one with the spark issue..

Im used to 2 strokes, Gas,Spark and compression, it will run

If any body has any ideas it would be helpfull...
Also i dont have cash to spend so dont leave stupid comments like, Get a new CDI or just get a new engine....
If i had the money i would...

Anything would be helpfull though..

Thanks

[JOEX]

A few things to look at....

Timing
Water in the gas
Flooded
Air flow restricted
Air leak in the intake system

But I suck at troubleshooting:p

[my88r]

just some thoughts

to big of pilot
make sure your mixture screw isn't to rich.

[StupidHurts]

Checked most of um..

If the timing was off,
It would backfire out of the carb or exhuast pending on how off it is..

Tried fresh gas
and as far as air flow,
Even if there was a leak it would atleast fire enough to get a pop or or anything..
But i think its more related to spark issue..

I must be missing something else...

DAMN 4 STROKES!!
But thanks anyway

[StupidHurts]

my88r-
I could see that if it dident run right or started hard but it doesent do anything...

But ill take it was an idea..

Thanks

[StupidHurts]

my88r-
I could see that if it dident run right or started hard but it doesent do anything...

But ill take it was an idea..

Thanks

[my88r]

heres a stupid ? is the fuse good.

[JOEX]

Originally posted by my88r
heres a stupid ? is the fuse good.
If the fuse was blown the motor wouldn't turn over.

[the Z Man]

Pretty easy to check the timing marks, it doesn't always backfire when its off...
Check and see how much tension is on the chain tensioner, if its almost all the way in, your chain is bad.

[my88r]

Originally posted by StupidHurts
but it doesent do anything...

[the Z Man]

Pull the lid off the airbox and the filter, try it then..

[JOEX]

Originally posted by my88r

But he says it has spark and compression....:confused:

[my88r]

Originally posted by JOEX
:confused:

me to......:tired:

[CSR400EX]

could be the decompressor on the cam.

[the Z Man]

Filter could be clogged causing too much fuel/

[StupidHurts]

The quad is stripped...
No air box..
ANd it really doesent matter...To much air, Not enough
Either way it would fire or do something....
Right now im looking into REALLY bad gas...
I jsut bought the gas but i put it into a clear bottle and theres a **** load of water in it....
There might be to much water that the gas wont even fire in the cylinder..
If that doeset work then the whole damn thing is getting soaked in gas and lit on fire...

But thanks for all the ideas....
Keep um comin

[formula1020]

i had the same problem and it was the plug connection at the c.d.i. box , i would check all your plug connections and make sure your battery is fully charged.

[xcracer416]

im going through the exact same problem, except i know that it wasnt winterized properly and it had bad gas in it. i pulled my head off just a second ago and i could tell that it wasnt getting something right. my timing marks was right on and i flushed the fuel tank and had new gas. im going to take my head to work tomorrow and lap the valves alittle and go through the carb with a fine tooth comb. have you been pumping the throttle when you try to crank it? cause if you have then you just flooded the livin crap outta it. did you just purchase the quad? when was the last time it was ran?

by the way the ex im having problems with i just got off a guy that has been in the pin and was needin some crack money. anyway hope you find something out. oh yeah i pulled the head also cause it has been leaking oil from the head gasket, so dont pull your head unless you have to.

[StupidHurts]

Yeah bad gas isent my problem..
I just drained the tank and bowl..
Tryed new gas and no different...
Iv tried crankin with out hitting the gas, iv tryed hittin the gas i even tryed spraying gas in the back of the carb...
Never changed..
Not even a pop..
I dont care if it has weak compression,weak spark or ****ty gas, it should do something...
I dont care what anybody says...
Theres a big problem somewhere and im gonna find it or burn that POS to the ground...Either Or...

Thanks Again

[BigBore24]

it almost has to be timing. i read through all your posts and didnt see you say you checked the timing marks on the cam. if you are already stripping it down i would def recommend it. get the motor in tdc by lining up the T with the notch in the top hole on the left side case. then pull the valve cover off and check your marks on the cam. the two lines should be horizontal and run parallel with the top of the head if you were looking at it from the side. the other thing is the decompressor like someone else mentioned but i dont know much bout those cuz ther only on stock cams.

[JOEX]

What happened the last time it ran?

Have you tried a new plug?

its the timeing most likly a timing pin

fly wheel pin

[StupidHurts]

Yeah next step was checking the timing..
I bought the quad not running
So......
Ill check it tomarrow..
Iv been busy today doing body work...I hate it..
But thanks

[JOEX]

Originally posted by 250r asm
its the timeing most likly a timing pin
Assuming you mean the flywheel key that's waht I was thinking too, it could be sheared.

But since it was bought not running who knows what the previous owner did to it.:ermm:

[400thacker]

can't believe that i found this thread. I AM HAVING THE EXACT SAME PROBLEMS. I just done a complete teardown on my quad. i didn't split the cases or remove the mag. it was running before.

first check the timing marks mentioned above.

make sure your motor is grounded well so you are getting spark inside the engine and not just on the frame.

check the keyway on the mag mentioned above.

when you put it into time, take the tensioner out. make sure that the 2 marks are lined up with your head on the cam gear and the lobes are facing down with the engine TDC and your finger holding tension on the timing chain through the tensioneer hole. you have to compensate for the slack in the chain or you could be off enough to make it not run.

make sure all your valves are seated well and closoing all the way or you will lose compression.

clean the carb and flush the tank and use highest available octane for optimum gas ignition.

make sure your rocker assembly is tightened down all the way just to be sure

check the suction the the spark plug in by putting your hand over the carb when cranking

I think that all that has it covered but i may be missing something.

if you have flooded the hell outta it you should take the plug out and crank it a few times and let it sit overnight. if there is excess gas in the cylinder then the cranking will get the most of it out and letting it sit should evaporate enough gas so it will start.

another suggestion if it is floded really bad or has in ignition problem...you can pull it behind a vehicle and roll start it. make sure it is in high enough gear. that will turn the engine fast enough that it may ignite bad gas or whatever. atleast you should get some sort of fire that way.

i have went through all of this except the main thing. cleaning all the gas out of the carb and tank and refilling with high octane and i didn't compensate for the slack in the timing chain when i installed the cam and chain. mine won't even start with starting fluid in the carb

the decompressor (if im not mistaken) is so one of your valves stay open when you start it making easier to turn over. if you already have compression problems then this could be an issue. a compression test will also help.

hope this helps you out. pm me and let me know how it's going. i will keep you posted on mine as well. thanks
Dan

[400thacker]

to check for the slipped keyway, put the "T" in the the window on the stator cover to get it reading TDC then take the cover off carefully not moving the mag. put a screwdriver in the sparkplug hole and turn the motor over by hand very little at a time and make sure that when the engine reads "T" for TDC that the piston really is "EXACTLY" TDC. i couldn't get the bolt broke loose to visually check the keyway so i tried this method and theoretically it works. you can turn the engine a little either way when you get it close rather than just turning counter-clockwise. with the stator cover on, it can mess up your starter clutches if you turn it clockwise.;)

[StupidHurts]

Ok
Just checked the timing and its perfect...
Then i thought maybe in a long shot the chain slipped around the cam gear and made it perfectly 180 Degrees out but the cam is good as well...
All the lobes are chewed up with some metel shavings but the timing is on...
So my problem is once again elsewhere...

Im lost...Freckin pluto man..This Quad is getting the best of me and iv bought some real pieces of ***DELETED***
So anymore ideas you guys might have would be good...

Thanks

[xcracer416]

if the lobes are shot then you have either had a rocker arm froze and kept to much pressure on the cam or you have an oiling problem. i would pull your oil filter cover and see if there is metal in there. I found my problem tonight on mine, since i didnt take the timing plug out of the side case i used a screwdriver like mentioned above. when i went to put the refreshed head back on tonight i saw that the t mark wasnt matching the piston stroke. i took the flywheel off and walla sheered key. but all in all the valves was in bad shape so four new ones with a fresh port job done wonders. i have a serious motor now that the key was sheered. im glad my wife dont know anything about mechanical work. :)

[fast2007]

Sounds like compression...Try this put a squirt or 2 of oil in spark plug hole,not a quart..LOL then get some starting fluid(dont kill it with that it want start if u do..)....you'll find out your problem then..I have seen quads have fire ,but wouldn't run..I got a ?? for ya do you have a key,not trying to say its stolen ,but if your trying to start wire it and dont do it a certain way it want run...Just food for thought..If u were in NC ..we would get it running somehow...LOL

[procircuit406ex]

Just a random suggestion, but have you checked the kill switch?

[BigBore24]

he says he has spark,the kill switch works by stopping the spark

[procircuit406ex]

your right i didnt think about that until after you said something, my bad

[StupidHurts]

No i dont have a key and it is hot wired but if that was the problem i wouldent have spark..But thanks any way...

[Bill Fuller]

Sounds like the starter is stuck (hung). Kicked my arse for a month, same symptoms fuel,spark,compression,timing ETC......Wanted to fire but never would.

[boosted3g]

have you took a look in the engine after you found metal peices? If i found metal in the oil and chewed up cam lobes it would be torn down and find out what else is damaged. Sounds like a top end problem and gaskets are cheap. I know your not looking to spend anymore but i would definantly take the head and valve cover off and inspect everything. It would set you back 20 bucks but it could save you a lot of time searching for the problem or possibly damaging something else.

[xcracer416]

did you ever figure that problem out yet?

[RATPACK Z400]

How about starter having loose ground or starter bad ,and check wiring for small cuts or breaks.and make sure all wire plugs and contacts are oil & dirt free.

[StupidHurts]

If the Starter was bad then it wouldent turn over..and i have spark...Maybe weak spark but enough to pop...

[400thacker]

my honda shop sent me the wrong rings causing me to lose all my compression. i suggest doing a compression test. i could feel compression with my finger over the spark plug hole but it wasn't enough to make it fire. if you rings are bad enough you will not start. if you have compression, spark and fuel then you are going to run unless you are out of time. i bet if you check the compression you will learn you could have saved some time. just my .02

[fast2007]

Like I said put some oil in the hole, then shut ether to it..

[Bill Fuller]

I never said you have a bad starter. I was describing my situation, one that was exactly like yours. It turned out to be the starter motor would hang and not let the motor turn fast enough to start. It sounded normal but just wouldn't "take off". Once we found that the starter was not releasing and fixed it she fired right up.

[imc188222]

First of all, I will buy it from you.

Second, I will try to help you if you want. You keep saying that you have enough of this and that so it should pop or do something. It isn't doing anything so obviously you are missing something.

As far as your fuel/air mixture. Gasoline has a very narrow f/a ratio inside of which it will ignite in a combustion chanber, go outside of that and it won't do anything. You can check if this is the problem by spraying gas into the carb with the throttle wide open while cranking it over. Using carb cleaner or ether can have you going in the wrong direction sometimes when used to diagnose whether or not you have a fuel problem. This is because they have a lower flash point than gas and their fuel/air requirements are not as tight, therefore they do not need as hot a spark or as much compression to burn.

I didn't see anywhere in the thread where you said that you did a compression check or posted the results. You need to do a compression check. When you do one, the amount of pressure that the engine can build is not near as important as how much pressure the engine builds on the first revolution. If I remember correctly, the engine should build at least 1/3 the final pressure on the first revolution. In basic terms, the needle should jump up quite a bit the first time the engine turns over and then go up a little bit more each time. If you could do a compression check and post what the pressure was each revolution for 4 R's that would be great. Also, hold the throttle wide open when doing the test. I have seen several engines that could build 130psi compression but would not run. They had deep scores in the cylinder and the tell tale sign was that they only had something like 25psi compression on the first revolution.

As far as spark, it is completely possible and common for the spark plug to fire outside the cylinder but not when it is subject to compression. You need to use a spark tester to test the spark, not the spark plug. You can get one at any parts store or small engine place. The simplest and most useful kind is one where you can adjust the gap by unscrewing part of it. I think the 400 coil should be able to produce at least 25,000 volts. If you want to buy a tester than stick a screwdriver into the spark plug boot and hold it so the shaft of the screw driver is 1/4-1/2" away from the engine and crank her over. The spark should jump the gap. This is the old school way. Don't blame me if you have a heart attack doing it though.

I guess thats about it for now. You have to do tests that completely eliminate things, not ones that "should be good enough" that is how you get in trouble.

I am not assuming that you don't already know everything I just wrote, just trying to help. Good luck.

[fast2007]

thats what the oil in the cylinder is for compression..Help it not slide by the rings etc..

[imc188222]

You can try adding oil to the cylinder and trying to start it but usually it just oil fouls the plug. Oil in the cylinder is more often used for a wet compression test. First you do a dry compression test and then add a teaspoon or two of oil down the spark plug hole and do another compression test. Compare the two and if you gained much with the oil then you know the rings are leaking badly. There are engines (no quads that I know of) such as a couple of honda car engines that can need oil in the cylinders just to get running again after sitting for a long time. These particular engines rings have very little tension and oil is required to re-seat them. Somewhat off topic but oh well.

[damon#6]

try cleaning ur starter terminals with some sand paper so u get better ground and better conection.. and does it roll over fast or is it a weak roll over ??

[StupidHurts]

ight ill figure it out myself..IM getting stupid a s s comments that we already went over...I know you guys are trying to help and i thank you for that...Some of these made some sense but i no longer need your help...Thanks anyway...

[imc188222]

I think you should pay someone who knows what they are doing to fix it for you. No offense, but these engines are about as simple as they get.

[StupidHurts]

Ok pay someone who knows what there doing...Alrighty then....You know maybe i could check the tire pressure..That might be why is doesn't start!!Go back and read some of the threads...Then tell me i don't know what im doing....No body on this god damn site knows what there doing....

[400thacker]

wow your comment bothers me. I understand that you already know it would be easier to take it to a mechanic. I believe that you know what you are doing and it's just a small overlooked problem but there is no need for comments like that. the words GO* DAMN are very offensive to alot of people here. we enjoy helping people when we can if we can and we are only trying to give information that you request.
from my personal experiences here most everyone knows whatthey are talking about. if it wasn't for this site i would have hundereds of dollars spent at my honda dealer on labor alone. if you don't need our misleading information then it's plain and simple DONT ASK. DO NOT DOWN GRADE THE PEOPLE ON HERE THAT HELP SO MANY OTHERS! Good luck getting our help in the future. thats all we were trying to do. if you checked everything that was mentioned it should start, thats the idea. if you can't fix it with what we tell you then you should take it to a mechanic. we know you pretty well know what your doing but sometimes you just need a new set of eyes. I would just appreciate it if you didn't talk that way about our site and friends here on www.atvriders.com. BTW this is the biggest internet atv site on the net and i think you should apprecaite that just a little and atleast take into consideration that it is possible for you to make a mistake and or overlook something. don't give up on it though.

[JOEX]

Originally posted by StupidHurts
If the Starter was bad then it wouldent turn over..and i have spark...Maybe weak spark but enough to pop...
Just because you have spark when the plug is out doesn't mean the spark is enough when under compression.