Hi just I have just bought a 2010 KX250f and i'm pretty pleased with it although I would like a little more down low power... just wanted to know if a power bomb and a good muffler with help with this?? I'm going to change jetting as well. also what about vortex ignition??

 

Try going up one on your back sprocket

 

351 Big bore.. can't imagine it without it.