Starting problems... need help

[beakerlsc]

ok so I ended up stuck working on a friends 400ex... it's bone stock and I believe it's an 03... several other people have tried fixing it before me and from what I've heard about it is a mess... I've heard it didn't have spark and that it did, that it was blown up and it wasn't, that it was out of time and that it wasn't, that there was gas in the oil, that some kind of switch was bad, and that the cdi (ignition module) was bad...
So since I've had it the battery was dead so I charged it, and it turns over just fine and has good spark, I've went through most of the electrical testing in a clymer manual (don't have the special peak voltage adapter to check the coil, exciter coil, or pulse generator)... it fires, but not right. To me it seems like it's out of time but I've been assured that it was in time, and the last 400ex I thought was out of time ended up just being valves slightly out of adjustment... so I checked the valves and they're fine. A friend suggested a bad stator and I'm leaning towards the cdi... tomorrow I'm going to go over to my parents house and grab the cdi out of my 400ex and try that. If anyone has any other suggestions it would be much appreciated.

[CJM]

What kinda of cdi does it have, stock or aftermarket?

[beakerlsc]

stock as far as I know

[CJM]

Ok, just wanted to clear that up b/c some of the aftermarket CDIs are off dirtbikes and dont work properly unless the battery is fully charged.

Id start with the basics:
1. Does it have compression-100-128psi is normal.
2. Timing must be verified, the cam gear must be checked and the cam itself (if stock) must have the decompressor on it and have the lobes facing down.
3. Its getting gas
4. Check the plug, all fouled out replace and try

Once thats all verified theres not much else you can do really. A bad cdi will cause it to not spark enough tho, could try swapping it if you have another 04 and earlier EX around.

[beakerlsc]

my compression tester doesnt have a small enough adapter for it
it seems like its getting fuel but i havent verified it
and i think todays project will be grabbing my other cdi and trying that and if that fails recheck timing

[tri5ron]

You said in your original post that you charged the battery, it turns over fine, and has good spark.

I think you need to concentrate on your fuel delivery.

First things first.
You also said that many people have messed with it before you, and claims of everything under the sun were made, as to what is bad. This indicates to me two things.
First a bunch of wanna-be's have touched it who have no business doing so,... and have probably caused more issues, than done any good.

And Secondly, this indicates to me that it has been sitting for a long time, and probably has old fuel in it.

Drain all the fuel.
replace with FRESH fuel.
check for any cracks in the intake boot.
check and clean Air Filter.
check for proper sparkplug, and proper gap.
Try starting it.

If it is still a No-Go,... start looking at the carb. somebody has probably been inside of there who shouldn't have been.

How old are these past "Mechanics", and How old are you?
How much honest experience, building and tuning engines, do you all have ?

and lastly, do you have a Manual ?

[beakerlsc]

i found the problem today... after re adjusting the valves and gapping the plug which looks brand new i got it to start but only for a second so i unplugged the cdi, cleaned the connections and plugged it back in and it ran for a bit but eventually died again so i tried my cdi from 400ex and that didnt fix it either and i figured it was a bad connection and realized that it was the wire going from the cdi to kill switch that had a poor connection and fixed it and now it runs great... until it ran out of fuel lol...
thanks for all the suggestions though guys, much appreciated