I have been trying to remedy this for over a month with nothing getting better (especially my wallet). It runs fine until it warms up then taking off from an idle is almost not an option. I have changed the reed petals, the mag. side seal and the water pump and case gaskets that go with doing that, and tried new fuel and air filter. I flipped it about 2 months ago and it was running great before. It got some dirt into the carb when I flipped it and I cleaned the carb and it seemed like it was ok for a week or two. I'm not sure where to go from here. I hope someone can help!

 

how are the carb and gas tank vents? are they clean and not pinched off?

 

they're all clear. It only does this on take off, once I can finally get it rolling it runs ok. It does kind of stutter at top end, when it finally gets there a little.

 

Did you pull the pilot jet out and clean/replace it? Its got to be a tiny spec of dirt in one of those openings, it doesn't take much. You may need a new carb

 

is that the one you have to have a pretty small flathead screwdriver that is down deep in an orfice? if so, then yes. I did notice that there is only one adjustment needle. Is it high speed, low speed, or air/fuel mix? I'm kinda new to the whole working on 2 strokes, I've been working on cars and trucks for about 20 years but this mikuni is a little different than a holley or edelbrock

 

air/fuel screw. both high and low speed jets are fixed other wise known as the main and pilot and yes that was the small one you mentioned.

 

could adjusting the air/fuel screw do anything? I am certain that there isn't anything in the main jet and when I cleaned this screw I counted in when i removed it and it was 1 and 1/2 turns out, so I put it back there after I cleaned the carb. Could richening or leaning it have any affect? I don't want to do something with it that could hurt the motor see as how the fuel mixture lubes the bottom end. Any suggestions?