Bike won't drive after it starts & warms up
I bought a new 2007 Kawasaki Ninja 250R in June 2008 from a dealership in Kansas for one of my sons attending Boston College. He drove the bike cross-country from Kansas to Boston and never had a problem. He used the bike in 2008, 2009, and 2010 in the Boston area. He stored the bike indoors at a friend's house during the winter months - always added Stabil fuel stabilizer to a full tank of gas per my advise, took battery out and kept it on a trickle charger. He never had a problem starting it up or driving it the next spring. The bike was properly serviced by a Kawasaki dealer in Cambridge, MA per the recommend maintenance schedule. In February of 2011, while bike was still in indoor winter storage, son leased a new car and did not use the bike when the spring of 2011 arrived. He failed to start it up and run it in the spring as he had previously done. Because he had a car and no longer needed a bike, I decided to go to Boston and trailer the bike home to Kansas. In preparation for this, my son took the bike out and tried to start the bike and found the battery was dead. He got a new battery. When he started the bike up, gas leaked out of the carbs. Bike was turned off and he had a towing service take the bike to the Kawasaki shop in Cambridge. The gas tank was removed, cleaned out, and reinstalled. The carbs were removed and cleaned...no damage to the carbs. New spark plugs were installed. Bike fired up OK. I arrived, put the bike on a trailer and towed it back home from Boston to Kansas in August 2011. Bike was put in the garage, kept relatively warm, filled up with clean gas and Stabil was added. I started it up periodically all winter long - it always fired up OK and ran as expected while on center stand. Last week I changed oil and oil filter using Kawasaki 10w40 synthetic oil, lubed chain, charged battery and fired it up. It took a while to get it started. Ultimately, I got it running as expected. When I tried to drive it after it was warmed up, it kept stalling when I released the clutch. I turn the throttle, let the clutch out and it stalls. Tried again and again and it keeps stalling. Tried adjusting the idle and still no-go. Now the throttle will not rev up the engine from idle (running at about 1400 RPM @ idle with the choke half-way). She fires up, idles, will engage first gear and turn the wheel while the bike is on the center stand. But it will not take drive when put in gear with both wheels on the ground. The gas is clean, the machine runs but it just won't rev up and run in gear. I do not believe it is the clutch or transmission or chain because the wheel does turn in 1st gear while up on the center stand. I am stumped and don't know what is causing this unusual problem. I have been riding about 40 years and have owned a variety of bikes including Kawasaki bikes. These include a different Ninja 250, a Vulcan 750, a Vulcan 1600 Mean Streak, and a Vulcan 1600 Nomad. I currently ride a Harley Sportster 1200 Custom. This is the first time I've run into the problem. The bike has 7,000 miles. Can someone help?