Hi there, im new here, im in the uk and have got a lt250r 86/87, i have the following problem, basically the quad as soon as its running the revs build and build untill its reving flat out, the slide is fine and free in the carb so isnt that, any other ideas anyone? im at the point of just dumping it!!!

 

check for intake leaks. spray all around with carb cleaner or starting fluid and see if the rpms change at all. make sure you dont have an idle set screw on the bottom of the carb holding the throttle plate open and make sure you dont maybe have a clogged airbox. too much air or too little might cause this to happen.

 

i tried that and it makes no odds, its doing the exact same thing still.....

 

you might have a diaphragm leaking in the carb then. have you rebuilt it lately?

 

no its not been rebuilt atall no, had a compression test done and its making 165psi so all good there, its really baffling me.....

 

buy a rebuild kit for your carb then. your probably running on 23 year old rubber parts.

 

you have an air leak somewhere another place to look is intake boot

 

check your left crank seal and the carb doesnt have a diaphram like a lawn mower. your left crank seal is exposed to air not oil. its behind your magneto and stator so if its leaking it pulls air straight in