Hi guy my kawasaki zxr400 is backfiring and not starting after l changed the CDI pliz help

Do you have a multi-meter and can check your cdi? The cdi is known as an igniter. It's what actually sends the signal to the ignition coil to fire down to the plug. If you can test your cdi and let me know, I'll see if I can find the specs - also, are you able to check your timing?

Valve is bent, stuck open. Pull the heads.

Check your coil and the cdi, sounds like they may be overheating and shutting down. Also check for possible vapor lock.

Hi hall ie
I just replied to your last question about firing order
I couldnt get back to you with a reply to your idle screw question due to a software problem
Has the bike been unused for a long time?
Please review your last 2 questions (which I've answered) & gimme some feedback as it helps my ratings
Ride safe
Bike-Doc

Bent needles can cause horrible throttle response. Start by installing a new needle that way you know its not the problem. If your carbs have rubber diaphrams make sure they arent ripped.