What would be the cause of your Engine to rev on its own?

Question

I have a 1987 KDX 200, and after about 10-20 mins of running perfectly normal the engine will rev out of control and I hit the kill switch to prevent blow up. It seems to do this only after it has gotten really warmed up. I've talked to people and read a lot, but not finding an exact answer to the problem. Any expert advise would be greatly appreciated. My own conclusion is the reeds, but not 100 percent.

Answer 1

not enough info...  is the cable sticking??

could also be a problem with the oil injection if your bike isnt premix??

Kawasaki..  not sure if your bike is one of the models with the rotary valve motor??(had a look dosent seem to be..)

Carbie problems could also be the cause..??

may be worth buying a set of reeds for it.. they arnt to costly to replace...

try this site,,  may help.

http://www.dirtrider.net/forums3/showthr...

Answer 2

Ghost in the Machine.

Answer 3

fuel mixture is too rich... how you adjust that is up to you, there are a few ways to change it, and a few things that can cause it to just be 'wrong' (which fixing those problems will of course correct it)

Answer 4

Make sure your not running around with the choke on lol. Or somehow  it gets lose or something even more strange .. >.<

Answer 5

Reving without reason on 2 stroke engines is caused by an air leak - intake manifold or crank seal.

When it starts reving, turn on the choke.

The added fuel will compensate for the air leak and lower the revs.

That's how you check if that's the problem.

Leaking reeds will allow the fuel to blow back through the carb.

Without enough fuel to the combustion chamber, will cause the engine to bog.

Answer 6

ya float has a whole in it.

Answer 7

If any of the obvious things are not the problem, consider the crankshaft seals.  Does it start hard?  If so, then that's probably the problem.

Answer 8

I agree with the above post, you got an air leak some where

Answer 9

i would be checking your float level, jets, throttle and throttle cable, not to sure why it would only do it when it was hot.