What causes 2stroke engine to rev on its own

Question

1987 KDX 200 and after warming up a bit it will start to rev really high on its own. Please help

Answer 1

The throttle is set so that the fuel air mixture supports a resonance between the intake manifold and exaust.  If it is lean, it will run faster. This is caused by an improperly adjusted needle valve or you have air leaking after the fuel inlet.

Answer 2

Throttle cable binding> Did you dump it or it fell over> had this happen many times>Move the handle bars back and forth> if reves up find where it binding or out of adj>

Answer 3

check for an air leak around the carb, top of the carb where the cables go thru ( it's top screws down too) and intake tube, sometimes it can get loose

Answer 4

The cold.

Answer 5

choke is sticking on your carb.  

Answer 6

Could be an air leak, or improperly tuned carb

Answer 7

Most likely a vacuum leak on or near the intake manifold. When warm and reving on its own try spraying a water mist around the carb and manifold. If the idle goes down while doing this you know you have a leak.

Answer 8

its having trouble idling

Answer 9

if you stop stroking it maybe it will go down