Vintage Dirt Bike Q & A

So far I have:
adjusted the valve clearances so that they are spot on.
changed the contact breakers and adjusted to correct gap
changed the condensor - had to resolder this
stripped the carb, blown it out with an airline and rebuilt
fiddled with pilot and throttle stop screw....wound them in and out

................and it still wont idle for more than 10 seconds......just slows and dies...unless I set the throttle stop very high.

It did idle before I rebuilt the engine to replace the kick startmech so obviously I have disturbed something along the line.
Any ideas please??

And just to further add insult to injury my 1978 CR250R with that so called "tempremantal two stroke" starts first kick and roosts

Filter clean? Did you remove the pilot jet and clean it to where you can see light through it? I've had to clean a carb two or three times more than once to get an older bike running right. Fresh gas and new plug, obviously. Another possibility is an air leak along the line if you just rebuilt the engine. But I suspect the carb is the culprit if it will run with throttle, but not idle. Keep on trying, you'll get there.

Thanks for your help.
I am sure its the carb. Going to get the airline on it later and blast it through.

I take the wire out of a bread twistee to help clean out the pilot jet. Good luck!