Engine revving by itself

[stubbracer]

Today when I was waiting on the startline for several minutes at idle and blipping the throttle once in a while, I noticed that the engine was reluctant to go down in revs. Eventually it started to rev really high all by itself so I had to put it in gear and hold it down with brake and clutch. In the race the problem dissapeared after a half mile. In the second race I did not wait at the starting line as long but I noticed the same reluctancy to go down in revs just before the start ( no problem in the race).
It seems that the time standing still with engine at idle is the problem. A fellow racer suggested it was time to change piston.
If that is correct please explain why it behaves that way or direct me to what you believe is the problem. Bike is KTM SX 360-97.

 

[smb_racing]

revving high is an indication of the engine running lean, this could be due to an air leak or dirty carb. I'd suggest removing the carb and cleaning it thoroughly. Good Luck.

 

[cr125_king]

Your idle adjustment on the carb might be to high??. Also your throttle cable might be adjusted out too much. Just a thought, these things worked(to fix the problem) when my bike was doing this.:)