Over Revving Problem
I am looking for some help/advice on my overrevving problem on my ninja 250.
I have a 2011 ninja 250. About 3 week ago as I was leaving work, I put the bike into 3rd gear and it started over revving. I stopped the bike. The throttle was fully released and was not stuck but the bike continued to overrev. I hit the kill switch and restarted bike and it was fine for the journey home. A couple of days later leaving a friends house, in 2nd gear this time the bike started over revving again. I stopped and it was showing revs of 6rmp even though I wasn't moving. I hard to turn off the bike again and restart and it was fine for the journey home. This happened a 3rd time again in a low gear. I brought it to a mechanic who cleaned out the throttle, said the cables were intact and the throttle has good spring in it. However, the day I picked it up from the mechanic's the over revving started in 5th gear this time. I was coming to a bend and tried to slow down but the bike kept over revving. I came off the bike. (I'm fine, I have good gear). The throttle has definately been off each time, it is not stuck. I am not convinced the problem is in the throttle anymore. My bike is back in the mechanics and he is saying the throttle is fine. What else could be causing the over revving on this bike?