I don't know if this is normal but after riding for a few minutes on the 2008 ninja 250, i come to a stop for a few minutes and it starts to idle above 2 thousand rpm. Why does it do this? and then after a few seconds it comes back down, and then back up. is it ok for the engine or what? cuz when i first start it up it normally idles at 1250 rpm. the normal idle speed. so my question is why is it going up above 2 and is it good./bad?

 

Your bike shouldn't be doing this. You don't happen to have the choke partially engaged? Is there any slack in the throttle control? (Meaning the throttle grip should rotate at least an 1/8th of an inch before opening up the throttle.) If there is no slack, just turning the front tire a certain way could make the throttle open a little on it's own.

Otherwise I would guess something is causing the engine to lean out randomly. Possibly a vacuum leak. Whatever the problem may be, I would take it back to the dealer for warranty work.

 

choke is not engaged and the is correct amount of throttle grip play. turning the tire does not afect the idle speed. But again after few minutes of riding or it seems once the engine warms up properly this is when the problem starts and the idle speed starts to get chopy, going up and going down. cant be good.

I was reading the manual and it says poor carburetor synchronizationq will cause unstable idleing, sluggish throttle response, and poor engine performance. the scary thing is im experiencing ALL of this!

WHAT SHOULD I DO?

 

It's possible, though not likely. Poor synchronization would also cause the engine to run rough. Have you tried to adjust the idle adjustment **** yet?

 

Wow...please share your discovery when you get it looked at...or when you look at it. Mine does the exact same thing and I can't figure out why. I synched my carbs last night, all vacuum lines are good, fuel level in the bowls seems to be right and my idle is still all over the place. It will idle right for about a minute after stopping at a light, and then it raises to around 1800 and hangs there for a while, then goes back down....over and over again. I'd LOVE to know what the problem is.

 

I'm not familiar with the 08's but I would imagine, as with almost every carb bike, that you should maybe turn the IDLE ADJUSTMENT **** down... normally a small **** on the left side of the bike under the petcock made specifically for adjusting the engine idle.

 

kawasaki got your bike covered for a year. give the dealer a call, set an appointment and make sure they fix it. otherwise there should be a number on your contract you can call and file a complaint. but i'm sure they'll take care of you.

good luck! keep us posted.

 

ya i will give the dealer a call thursday morning and make sure they check it out. my bike only had 5 miles on it when i noticed this issue. why wuold a new bike be doing this. so frustrating.

oh and if it idles properly at startup, wouldnt adjusting the idle screw just make it idle even lower and then the engine would shut off. that i dont understand how it would help.

 

mine did that also, i looked in the owners manual and our bikes have a adjuster screw on the left side of the bike. Its a black ****, turn it to the left to lower the rpms.

 

it is probably just idling high, if the adjustment screw does not fix it then you have look deeper