I want to know if anyone knows if a bad CDI can ruin or damage a coil ?


I have a bad coil and I'm replacing it. I was told by someone that if my CDI was bad it could ruin my new coil. I don't have the peak reading adapter for my multimeter to test my CDI to check before putting on the new coil.

I know the CDI accepts the charge from the stator, holds it and at the appropriate time releases it to the coil where it is intensified and sent to the plug to provide spark for combustion. I don't see how the coil could be ruined by the CDI, but my knowledge on this electrical stuff is very limited so I figured I'd ask those that are better informed.

Thanks

 

Have you checked the resistance in the coil to makesure it is truely bad?also there are 2 coils on the ds650 so it would be kind of hard to have both be bad at dsame time. I do not beleive a CDI could ruin a coil. I think maybe you will find that your CDI is probably the faulty part and was fried because you had a bad ground which causes an incomplete circuit which will then cause things to fry .

 

I'm going to take the bike apart and check every wire and ground. I did check the resistance of the main coil and it wa supposed to be .3-.5 and mine was .9 I'm not saying the stator coil isn't bad, just haven't checked it yet, and since I know the one part is bad I went ahead and ordered a new one. Thanks for the adivice.

 

No a cdi can not hurt your coil. forget ohms put a postive wire to the + coil lead then take another wire and attach one wire to the - coil lead let the other end wait for a moment. then insert a used or any plug into the coil wire grounding it to the engine NOW You are ready to test the coil make sure your bike is grounded in all three spots correctly then strike the other end of the aformentioned ground from the coil to a ground on the bike if the coil sparks it is good.I like seeing a good 1/8 to 1/4 bright orange or blue spark.That is what your cdi dose it creates a magnetic ground pules induced by the stator to a already hot coil.to complete a spark sequence.BUT HEED FLD"S WARNINGS ALL GROUNDS MUST BE GOOD!!!!!!![img]i/expressions/face-icon-small-wink.gif[/img]

 

Thanks Azsand !
Now do you have any knowledge you can impart regarding the testing of the stator?
I'm trying to figure out where my problem is adn I'm just banging my head against a brick wall at the moment.

carb is good and clean, valve clearance is dead on, gas is new, fuel filter is clean, New plug, air filter is clean,properly jetted, no exhaust leaks, new battery....... only thing I can think of is electrical. It sputters when it starts revving up, and runs like crap from near half throttle on. it falls about dead after sputtering and seems like it's hitting the rev limiter WAAAy early and running like junk. even when it idles it sounds good then hits a rough spot - this I can even feel when idling with my hand behind the pipe. it has a constant pressure then lacks pressure in one spot then picks back up - you can hear it too. and under load it gets worse.
I'm no mechanic, but no fool either...... any suggestions ?

 

I might be able to help if you explain to me more about your bikes set up do you have excessive lighting. to make it simple to start the trouble shooting take and install a volt meter fast response digital type to your battery try the bike out moniter what happens with your voltage during this troubled area.I can tell you most voltage shortage stammer take place at full rpm's.and if it is a voltage problem due to lack of amperage from the stator it will become much more prevalent when you hit your HIbeams and break lights at the same time. while running the bike @ higher rpm's. And once again grounds will create the problem you are speaking of.IM TELLING YOU GUY"S SOME DS"S ARE VERY GROUND SENSATIVE ON BOTH OF MY PAMI"S I HAVE A #4 BATT CABLE FROM THE BATT TO GROUND ON SUD FRAME. THEN A #4 BATTERY CABLE FROM THE SUB FRAME TO THE MAIN FRAME.THEN A #4 CABLE FROM THE MAIN FRAME TO THE ENGINE.THEN A #8 WIRE FROM THE ENGINE GROUND TO THE STARTER GROUND BOLT.I dune these bikes they have fully lit whips and baja lights and noss.So amperage is very important to keep under control.OH every ground area is sanded clean a tad ugly but very effective.[img]i/expressions/face-icon-small-happy.gif[/img]

 

this definately sounds like a bad CDI had the same problem myself, and ofcourse its fixed now.

 

<div class="FTQUOTE"><begin quote>Originally posted by: AZSAND

I might be able to help if you explain to me more about your bikes set up do you have excessive lighting. to make it simple to start the trouble shooting take and install a volt meter fast response digital type to your battery try the bike out moniter what happens with your voltage during this troubled area.I can tell you most voltage shortage stammer take place at full rpm's.and if it is a voltage problem due to lack of amperage from the stator it will become much more prevalent when you hit your HIbeams and break lights at the same time. while running the bike @ higher rpm's. And once again grounds will create the problem you are speaking of.IM TELLING YOU GUY"S SOME DS"S ARE VERY GROUND SENSATIVE ON BOTH OF MY PAMI"S I HAVE A #4 BATT CABLE FROM THE BATT TO GROUND ON SUD FRAME. THEN A #4 BATTERY CABLE FROM THE SUB FRAME TO THE MAIN FRAME.THEN A #4 CABLE FROM THE MAIN FRAME TO THE ENGINE.THEN A #8 WIRE FROM THE ENGINE GROUND TO THE STARTER GROUND BOLT.I dune these bikes they have fully lit whips and baja lights and noss.So amperage is very important to keep under control.OH every ground area is sanded clean a tad ugly but very effective.[img][/img]</end quote></div>



No additional lighting on my bike. Engine is stock 06 Pred 500. I did put on a full HMF exhaust, K&N filter and jetted it. It ran fine like this for over a year. Then it sat for about 6 months. I took it out and it was running fine, then while in some tight steep hills where I had to clutch it a lot and keep in lower gears it started popping and sputtering like it had foulded a plug or something. The when I stopped at one point it wouldn't start back up - no lights no click no nothing. I took it home and got a new battery. since then it popped and sputtered when I tried to get the RPM's up. and it also runs rough at lower RPM's - when I'm going with steady 1/4 throttle it doesn't feel smooth it kind of hits a rough spot. when idling it seems like it hits this rough spot in the same p[lace every time. I can put myhand behind the pipe and it runs fine then a loss of pressure on my hand and it sounds like it hits a rough spot at the same point.
I checked the coil and it had a high resistance number so I ordered a new one. I shoudl have that in a few days. I plan on going over EVERY ground to make sure they're ok. I wasn't sure if this was a problem that could be caused by the CDI or not. Someone was telling me that the stator could be my promlem.
Any help you can give is greatly appreciated.