my daughter also has a viper 90 that won't start, we replacedthe cdi box yesturday and the coil prior to that but still no spark, any ideas?

 

go to www.anythingatv.com they have trouble shooting and how to check electrical componets hope this helps

 

more than likely it probaly a stator cheapest I found was Rm stator

 

Off of the CDI should be a black wire with a white stripe. pull back the plastic covering the connections, but leave the connection in tact. Now ground this connection to the frame or to the negative terminal of the battery and see if you have spark. This bypasses the upper controls. If you have spark, you have a problem with either the kill switch or the main key switch.

If still no spark, check your stator and then your coil.

I just went through this on an 04 predator 90cc.. replaced the stator and the CDI, only to find the key switch had a bad contact. Shot he connectors and inside the switch with some electrical cleaner and now I have spark.

 

I would try the stator. The spark is built in the stator the cdi box stores it and sends it to the coil then to thr plug that is most likely your problem anythingatv.com has the part and they are fairly cheep. but i think they are oem eton parts.

 

I replaced CDI box coil stator so that no sparks have no power coming out of the white and blue wire from the CDI box to the coil should there be power and what voltage

 

See this https://atvconnection.com/forums/chi...-question.html I answered earlier this week. However on most Chinese/Taiwanese bikes blue white is the wire from pulse coil on stator to CDI, it produces a low voltage pulse to tell the CDI when to fire. Check the "help diagnose stator" sticky in the Chinese engines section of the forum, on how to check coils etc, but different makes have different resistances and voltages so don't take readings as gospel.