This sounds like your idle jet need to be cleaned or replaced, try runing a few tanks of B12 or some other carb/fuel injector cleaner threw it and see if that helps if not you may need to rebuild the carb.
Hi, Anonymous for this scenario you will need your service manual that has all fastener torque specs and a wiring diagram on the back pages, parts fiche, and owners manual if you can't find the best tool you ever bought for your Kawasaki, despair not, for a mere zero $0 you can download another one.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
Fuel Switch Valve Ninja 250
Cleaning Fuel Filters Ninja 250
Kawasaki Ninja 250R Service Manual
OEM Parts for Kawasaki
2006 Kawasaki Ninja 250R Owner Manual
The max capacity or weight recommended by Kawasaki is 330lbs but you can ride two people max
if there is no free play when pulling the lever in, the bike will most likely take off from first gear, but when you throttle it, the clutch will most likely slip. if the lever is to loose, lots of free play, you may have a hard time getting it in gear. approx 1/4 inch free play with the lever and it will work normal... unless its ready for a new clutch. hope this helps...
YOU NEED TO SERVICE THE ENGINE
i porsonaly woulden't recomend that because your fram and syspension aren't men't for the extra weight and power! also the 250r is a twin and the 650r a inline 4 so it will be to wide for the fram and cowling's