need help. bike reving flat out when i start it

[hyper_irl]

can anyone help me? as soon as i start my bike it revs flat out, and then dies when i take off the choke. bike is an 87' kdx 200. bike ran out of petrol last time i was out, and was lying up for about 5 weeks. i already drained the tank and cleaned it, new air filter, new plug, took apart carb and cleaned it (about 7 times). i found a piece of crap in the jet and thought this was the problem but its still the same. i noticed a small piece broken out of the corner of one of the reed valves ( really just like a pin hole). could this cause it? when i start it up it feels like when it is low on petrol like reving up like mad and then half dying. anyone got any ideas?

 

[dcal]

last bike that did that to me, it was the slide valve not closing all the way.a possability?

 

[Rhodester]

You have a vacuum leak. Maybe a large one by the sound of things. The choke richens the mixture enough that it just runs lean enough to rev to the moon when it starts. When you pull the choke off it's so lean that it just dies. I'd check around the cylinder and head gaskets as well as the reed valve gasket and the condition of the intake manifold (cracks).