I have a 250 08 ninja, the idle is good when not giving it gas. But once you give it gas and it returns to normal idle it take about3-4 seconds to idle normally(2500 t0 3000 rpms) It does it every time even when fully warmed up. It goes to 1500 and slowly goes to normal. Anyone has the same issue? Is it just the carburated model or does it need some adjustment? Thanks for any input.

Idle mixture screws.

Sounds like it's a little lean at idle.

There are two idle mixture screws hidden under caps that must be drilled out. I recommend you google "mixture screw ninja 250r"

---- That should pull up the exact link to the ninja faq with detailed instructions.

However it may be smart to wait for a second opinion before taking power tools to your carbs.

jetting or vacuum leak.

.... But once you give it gas and it returns to normal idle it take about3-4 seconds to idle normally(2500 t0 3000 rpms)

2500-3000 rpms is not normal idle speed. 1300 +/- 50 rpms is normal for a fully warmed bike. If your idle speed is up to 2500, something is wrong.

Any modifications to your bike? (i.e. carbs work, exhaust , etc...)
Does the bike run OK at 1500 rpms?
Have you tried adjusting the idle speed?

Yea, it's a little confusing when OP is saying 'normal idle' is 2500-3000.
So it is at 1500 and then slowly goes to 'normal'?? 1500 is already above the real normal. Is your choke on?

Both the ninjas I have call for idle to be 2500 to 3000. I could be wrong.

Both the ninjas I have call for idle to be 2500 to 3000. I could be wrong.

Where did you get that from?
Attached is from the service manual for 08+ 250s

1300 is ideal.

Where did you get that from?
Attached is from the service manual for 08+ 250s

Yes you are right I miss read the numbers for both.