ignition problems

[dcollins4328]

I have a 1993 kx 500.  It started fine and ran for several hours, them, it would'nt make enough of a spark to run, it would only backfire.  I replaced the cdi and ignition coil on the stator.  It ran fine for several hours, then slowly lost voltagge or something, and eventually it wouldn't run?  I am frustrated, any help would be apprieciated.

[MadKaw]

check timing?

[KXcam22]

dc,
  Sounds suspiciously like a sheared flywheel key.  When you replaced the ignition coil are you talking the stator inside or the timing pickup coil. Did you remove the flywheel to do this?  Also try disconnecting the kill switch as they can fail closed (grounded) sometimes.  Let me know. Cam.

[dcollins4328]

I replaced the ignition coil on the stator plate with a moose coil.  I had to remove the flywheel to do this.  I also replaced the woodruff key, so i know that's not what it is, and I sodered the wires together.  It will make a spark;when I pull the plug out of the cylinder and kick the bike over, I can feel the spark with my hands, but it is weak.  How do you change/adjust the timing?

[hughes]

I replaced the ignition coil on the stator plate with a moose coil.  I had to remove the flywheel to do this.  I also replaced the woodruff key, so i know that's not what it is, and I sodered the wires together.  It will make a spark;when I pull the plug out of the cylinder and kick the bike over, I can feel the spark with my hands, but it is weak.  How do you change/adjust the timing?

Have you removed the flywheel to check the key? The flywheel and the crank shaft are a tapered fit. Dirt,grease,oils will keep the tapers from locking together. The key is just a way to aline the flywheel. The locking tapers is what keeps the flywheel from spinning on the crank.

[gowen]

I replaced the ignition coil on the stator plate with a moose coil.  I had to remove the flywheel to do this.  I also replaced the woodruff key, so i know that's not what it is, and I sodered the wires together.  It will make a spark;when I pull the plug out of the cylinder and kick the bike over, I can feel the spark with my hands, but it is weak.  How do you change/adjust the timing?

What about the coil under the fuel tank? That sounds like your issue... Also check your spark plug cap. It could be bad, I had your issue.. I cut the wire at the cap and purchased a cheap cap from Dennis Kirk.. Life was back in my spark.. This was all before replacing my ignition with PVL. Check your wire.. Take the spark plug cap OFF and give it a solid kick, I'm going to bet you will never do it again.

[dcollins4328]

Is the plv setup expensive?..I'm about ready to give up...I have replaced the spark cap and coil under the tank, and the cdi, only to have the same problem, weak spark after several hours of riding.  I know that the flywheel key is not the issue, and the stator and flywheel area are clean.maybe I should just replace everything and upgrade.

[KXcam22]

This is a curious problem.  I am assuming that the moose coil is also a lighting coil.  Does it alwasy run ok for a few hours then lose spark? Generally an ignition issue that happens after riding for awhile (specially if it is repeatable) is due to a component heating up.  I would suggest borrowing an ignition pickup and trying that (the external thing that triggers the spark).  They have been known to go bad without failing completely.  Also, when you put a new plug cap on it is advisable (what Gowen was describing) to cut the plug back 1/2" or so. The first bit of the wire gets corrosion inside from the old plug cap connection.  Hope this helps. Cam.

[FuriouSly]

Just a couple questions for you.

You sure it is spark and not an airflow issue?  Sometimes reeds get weaker with use and heat and do not let the proper fuel/air mix in.

What plug are you running?  Might want to run a better quality hotter plug.

What is your compression?  Old top end will run like crap after it has a chance to warm up and get under load.

Just some thoughts...

Hey Arigato,  this sounds just like Jimmy's KX5.  What ever came of that ghost in the machine?  He get it built by ArtL?

Sly

[dcollins4328]

I had it replated with nikaseal and a put a fresh top end in it.  It also has a new boyeson reed cage.  I am running a br8, but have tried a br9.  It always ran fine for several hours, then I'd let it sit for a day, or several hours, then try it again and it would backfire, and run like crap, then die.  When it was running right, it would start with one kick cold, so I think everything else on the bike is fine except something with the ignition.