Here is a tuff one for alot of people i cant find any one to figure it out. ok my 84 250r starts first kick idles great i ride it around just fine after alittle while it starts revin really high but it is not the throttle stickin and when it starts to rev high the kill switch wont turn it off we even pulled of the spark plug wire and it still wont kill i got told that it is carbon built up on top of the piston but i cleaned that up and it still does it. it has been sitting for over a year. the intake has a leak in it i thought it was gettin to much air but why wouldnt turn off with the kill switch. if you got any ideas please tell me thanks.

 

You answered your own question, you have a known problem, an intake leak which is causing a lean condition, its getting your engine hot enough to continue to ignite fuel with out the help of the ignition system. you are lucky you have not seized the piston yet. get that intake leak fixed ASAP!

 

Thanks man i will get that fixed and see if it helps

 

Yes a leak in the intake/boot will allow air to lean out the mixture, like battman said get it fixed be4 you ride it again because if it is running without a spark who's to say when the mixture will ignite in the stroke, it could be on its way up.

 

it diesels in case you didnt understand...

blasters do this too, probably others.

 

yeah its mainly because they have so much compression, but still very dangerous in a gas engine