I'm not familiar with 2-strokes, except lawnmowers and weed-wackers. But, here's my 2 cents anyway.
1) Check to make sure ignition timing is correct.
2) Make sure the carb is sealed, with gasket and gasket sealer to the intake manifold. Air leaks here cause rough idle, but aren't as noticable off idle.
3) Open up the carb and make sure the slide needle is fixed to the bottom of the slide. If the needle can move up and down you'll get very erratic running.
4) The carb slide should not rattle in its bore or it will let too much air pass.
Finally, if all these answers sound like I've only ever worked on 4-strokes then change your question to match my answers.
1) Check to make sure ignition timing is correct.
2) Make sure the carb is sealed, with gasket and gasket sealer to the intake manifold. Air leaks here cause rough idle, but aren't as noticable off idle.
3) Open up the carb and make sure the slide needle is fixed to the bottom of the slide. If the needle can move up and down you'll get very erratic running.
4) The carb slide should not rattle in its bore or it will let too much air pass.
Finally, if all these answers sound like I've only ever worked on 4-strokes then change your question to match my answers.
