No spark after replacing piston and rings

[pcbisnice]

Hey everyone. I recently replaced my piston and rings on a 90cc roketa Chinese ATV. It has no spark issue before. Now after putting everything back together I have no spark. I did not touch anything in the ignition system. I'm really stumped on what this could be. I'm sure I'm just overlooking something simple. Any ideas or suggestions would be greatly appreciated.

So far I have tried a different spark plug and also removed the kill switch pin from the CDI to bypass the kill switch with no change.

[pcbisnice]

After looking over the wiring harness I noticed that theres only one ground wire, its from the battery. Is that normal? I don't remember ever disconnecting a ground when I pulled the engine out to replace the piston and rings.

[buzz]

Hello You had to remove a ground from engine if you removed engine from atv, should be a green or black wire. Hope this helps,give it another look by the starter and other engine case bolts.Try running a jumper wire from engine bolt to ground on battery,then check for spark. Got to be something simple. Good luck.

[pcbisnice]

Originally Posted by buzz

Hello You had to remove a ground from engine if you removed engine from atv, should be a green or black wire. Hope this helps,give it another look by the starter and other engine case bolts.Try running a jumper wire from engine bolt to ground on battery,then check for spark. Got to be something simple. Good luck.

I really appreciate your response. I will try that.

[pcbisnice]

If I put the spark plug in the spark plug wire and hold it against the side of the engine and complete darkness I can see a tiny bit of intermittent spark. It seems to come and go randomly

[buzz]

Now its sounds like a bad coil now or cdi ,cheap stuff replace 1 at a time. so you know which one was bad.

[buzz]

Hello again ,well did you get running?