People on here are very cautious about giving advice, because every bike, and environment can be different. The tuning section on here -> http://www.nsr-world.com/tuning/250-tuning/carburation%20index/jetting/ gives a fairly good account of the NSR specifics, and when matched with this article -> http://justkdx.dirtrider.net/printcarbtuning.html although based on another manufacturer I think you will be able to work it out. Especially the quarter throttle tuning section. Cheers.