I have a 87lt250r with a Keihin PJ 38mm I'm haveing a little troblem getting the jetting right, I'm useing a K&N filter Slip on it also has a FMF Fatty w/ Power core silencer. LS jett 48, Needle Clip 4 pos, Diamerter is a letter L, and HS jett is 170. Bike start up fine Idle's good when I let it warm up and go to take off at about 1/4 th. it seem like it's loaded up from idleing but clears up after I get threw 2nd and 3rd gear and after riding for a while there is no problem when shifting threw all the gears. Did a plug check and it seems to be running rich in the mid range. Can i go all the way to the top notch on the clip(needle) Or should I go next size diameter needle, it's the gold color needle with the 3 letter lable system which would put me into M. Any help would be great........

 

No matter how good you have a two-stroke jetted its going to load up when just idleing. Its just the nature of the motor. If it doesn't run poorly, and carburates smoothly I wouldn't mess with it.