TTR-125 won't idle!!

[cybermecium]

Put an FMF powercore IV pipe on my little bro's TTR125. Installed a 110 main and 17.5 pilot jets. The bike will only idle (SLOWLY) with the choke on, and dies when the choke it taken off. Yes, I warm it up completely before I take the choke off and the RPMs still drop off until the engine dies. Ive adjusted the air screw etc all friggin day and it still doesn't idle without the choke on. What's wrong with this damn thing? Thanks,
Jake

[mxchic]

When the choke is on the bike is running richer. If it only wants to idle with the choke on the bike may be running too lean on the pilot. What is the stock pilot jet? You can call FMF and see what their jetting recomendations are for this exhaust system. You can also check the carb to make sure their is no sedement clogging up any of the jets. Spray it down with some carb cleaner just to ensure it clean. Check your idle screw and make sure it is not turned too low. You said you adjusted the air screw. Also make sure exhaust and air boot into the carb is secure and there are no leaks. My suspision is that the bike is just running too lean.

[Dirtbikindad393]

MXchic is right. If you have a pipe on it I would suggest doing the air box mod to start with. As far as it idling check the fuel screw and make sure its not closed up all the way. If its fine I would check the jets and make sure the pj isn't clogged. Try a 20 pj and see if that helps. What elevation are you at? What are the temps?