A bad sparkplug could cause no spark, or sparkplug cap/lead, or a faulty ignition coil.
Is the speedo display showing any warnings ?

 

I tried another spark plug and it’s a brand new coil. I tried a working used one too. Speedo comes on where should I look for warnings?

 

I suppose you have checked both fuses, and the ignition and kill switches are both working, and power is getting to the two cdi/ecm power in wires, and the earths are good. Then checked for continuity between the cdi and the coil, and it's earth if it has one. Checking the continuity of all the ignitionwires would be a good place to start.

The sparkplug cap or leads could also cause a no spark..

That's about all the things to test, but you should probably download a service manual and do the tests for no spark.. It will lead you through the most logical process of checking and elimination.

 

In addition to Mechs recommendations, check CDI itself.
Test for continuity between ground pin and all the other pins.
If it has continuity, there is an internal short.
Basically, Mech provided a road map to eliminate CDI as a problem by testing on either side of the component.
The test I recommended will verify the problem is the CDI if there is in fact an internal short.