Lynn-

also one other thing i will add, because i didn't think it was important, at the time i thought it was a carb adjustment, but i'm not so sure now. when i got the quad running two weekends ago, when i was riding it, it wouldn't go past about 1/4 throttle, or it would die. as soon as you released the throttle it resumed running properly. if you rode it and stayed under that mark, it ran perfectly fine. if you went over, it would start to bog down and if you kept on the throttle it would die. at the time i thought it was a carb adjustment, but could it be CDI related? Or anything electrical?

Thanks again.

 

well i haven't heard from Toby yet, so I went ahead and just bought a new ignition coil for 10 bucks off ebay. it looks just like mine. he seemed to think that's what i messed up, is the coil. ebay also has a few of my CDI's that are identical to mine...i wasn't sure which to get first, and as i'm short on cash right now i had to choose. as he thought it was my coil, i figured i'd give that a chance.

i appreciate all of your patience and help thru this, especially Lynn who's been there every step of the way so far. it means alot that you guys take the time to help me out. thanks again.

 

I looked at the procedure in the link. It has you measure resistances of the separate stator windings (which is good and valuable information), but I think the stator voltages (all AC of course) are also important to measure. If a stator winding is open, or completely shorted. the ohm meter tests will find it. But if you have a shorted turn inside any of the windings then the resistance will be in spec but the output will be really really low.

What causes them to fail? They are cheaply made, run in a really hot environment with lots of vibration. On my quad they are air cooled through a fan which often runs under mud and water which get into the works. Even with all the abuse I give it mine has never failed.

You have found an interesting link with the CDI on eBay. As I said before I haven't seen or heard of these CDI's before. I'm an adventurer. If it were me I'd buy one and try it. If it doesn't work I would take it apart and see what's inside. But that's me.

The stator doen't make spark. The CDI does that through the ignition coil. The stator generates moderately high voltage AC to power the CDI on one winding, and another winding generates a low voltage timing signal which thells the CDI when to dump the energy accumulated/stored from the power winding into the coil.

 

This is a difficult question. I would suspect the carburetor because that would be the case the vast majority of the time. But I can also see electrical stuff breaking down with increased RPM. Everything gets bigger in the electrical section with increased RPM. The voltages produced by the stator are linear with engine speed. I can see a scenerio where the eletrical system works at low RPM (and lower voltage) and then arcs over at higher RPM. But is unlikely compared to a gummed up carb.

 

I think you made a wise choice based on available information. Maybe it will solve it, and maybe not. If it doesn't, then maybe we need to retrench a bit, make some stator voltage measurements, and look into a new CDI).

 

I think i might have just figured something out......remember how i said i had intermittent spark?? well the plug seemed to always spark better facing down or something like that......and i couldn't figure that out....but i just remembered last weekend...one time i was taking the plug out for the umpteenth time lol, and the boot fell off the wire! maybe...just maybe...that is why i had been getting intermittent spark!? because sometimes contact was made properly, and other times it wasnt! does that make any sense? maybe...the intermittent spark was due to that rather than a bad CDI or stator? maybe those are ok after all...

however i tightened the boot back up last weekend and still got no spark. but maybe because by that time i had done too much damage to the wire and/or coil from cranking it while improper contact was being made and having the cap fall off 4 times while the machine was running. who knows. can't wait to get this coil, maybe it'll shed some light.

 

another quick question. just how important is it to ground the spark plug when checking for spark? could it damage the wire or coil to crank the engine 150 times without grounding the plug? because ive kicked this quad a heck of alot without having it grounded. come to think of it, the times i seen the spark the best were when it was touching the frame.

 

I usually ground to the engine case or fins on the head.. Not sure about damage from not grounding a plug while checking.. But you wont get a spark at all if its not grounded..

Lynn? any thoughts?

 

Bad connections at low voltage can cause lots of problems. Bad connections at low voltage with lots of current passing through it causes even worse problems.

Bad connections at really high voltage (and low current) such as the output of the ignition coil don't matter a wit. The high voltage will just blast through a bad connection. After all the spark plug gap is a *really* bad connection when you consider the air gap across the electrodes. It just blasts it way through...

 

Since the really high voltage on the ignition coil secondary will "blast its way through" to ground it is really important that a path is provided that will safely pass this energy to ground without it traveling internally through the coil itself, or worse traveling through the coil and through the CDI and then to ground.

In thunderstorm prone areas we put lightning rods on houses to provide a safe discharge path for the really high voltage lightning sparks. This keeps the lightning from traveling through the kitchen to get to ground, which would not be good for the kitchen.

Thus you should keep the spark plug threads grounded during spark tests. The spark plug is the lightning rod that keeps the voltage from rising too high and taking another more destructive path.

That said, I've made the mistake of leaving my plug wire disconnected and trying to start my quad. I've never had a problem with that, but it is not a good idea.