Kawasaki KXF450 2016 wont start

If you have checked all the obvious things then unfortunately it may be time to take it to a local shop. Some times that is a cheaper route than if you start replacing electrical parts because they are not returnable if it is not the problem. I hope you have a good shop close enough to take it too but it does seem to me if you had problems after replacing your piston then something related to that is where you should start looking.

This is what I would check next. You may have already done these checks.
Try a new spark plug. Make sure it's gapped correctly.
Does it have compression? (Valves aren't closing, hole in piston, etc...)
Does it start if you take out the spark plug and squirt some gas directly into the cylinder? (Fuel delivery related)
Is the timing correct?
Is the timing chain installed correctly? (so the valves are opening at the correct time)

Air in the FI system perhaps? I'm not sure how this would happen or what the procedure is for purging.

For some reason I suspect your injector is not adequately/properly supplying fuel. Just a hunch.

pls help!!! Much ty

Radical wrote:

This is what I would check next. You may have already done these checks.
Try a new spark plug. Make sure it's gapped ...more

Radical wrote:

This is what I would check next. You may have already done these checks.
Try a new spark plug. Make sure it's gapped correctly.
Does it have compression? (Valves aren't closing, hole in piston, etc...)
Does it start if you take out the spark plug and squirt some gas directly into the cylinder? (Fuel delivery related)
Is the timing correct?
Is the timing chain installed correctly? (so the valves are opening at the correct time)

...more

Nothing is going to ignite if you take the spark out. That said, I'd check the cam chain as this guy mentioned last.

If you can try a new coil!
Had a similar problem with my KX250f 11, changed the coil and everything was good.

When i removed the spark plug and kicked it i had a spark but in the end it was not strong enough.
Search for days at the beginning the engine starts for some time and than it stopped wouldn't start again.

Its worth a try.

Radical wrote:

This is what I would check next. You may have already done these checks.
Try a new spark plug. Make sure it's gapped ...more

Radical wrote:

This is what I would check next. You may have already done these checks.
Try a new spark plug. Make sure it's gapped correctly.
Does it have compression? (Valves aren't closing, hole in piston, etc...)
Does it start if you take out the spark plug and squirt some gas directly into the cylinder? (Fuel delivery related)
Is the timing correct?
Is the timing chain installed correctly? (so the valves are opening at the correct time)

...more

seth505 wrote:

Nothing is going to ignite if you take the spark out. That said, I'd check the cam chain as this guy mentioned last.

seth505 wrote:

Nothing is going to ignite if you take the spark out. That said, I'd check the cam chain as this guy mentioned last.

...more

Of course!
You can't squirt gas directly into the cylinder without removing the spark plug. I thought it was common sense that the spark plug would have to be re-installed before trying to start it .

You can remove the kill switch just to rule that out. At this point you just need to start swapping out electrical parts...

Sometimes kawasakis do that shit lol jk

But yeah my guess would be timing first. And if that's correct electrical most likely. Replaced the entire bottom and top end on my YZ450f one time. Got it all back together at midnight that night. Wouldn't start. Sure enough was one tooth off on the timing. Anyway good luck!

Take it in, pay the 200 it costs to have it fixed and ride it!

Battery is most likely dead. do you get any sound when you press the start button ?

Speaking from recent experience, make sure you installed the stator cover correctly. My KX ran like shit then wouldn't start so I pulled it and saw I was not paying attention and installed the stator without the clip for the wires, so flywheel went snip snip. Also had a gnarly get off well before the top end build and it jarred the stator connector loose. I kicked for days until I noticed it. After that, I'd start testing coils. If your timing was off you'd already be fucked and be replacing everything in the top end again if you rode it.