i wouldn't do it. First a 250 four stoke is like owning a 125 2-stroke. Second my freind has a kfx250f andi rode that thing and it sucked. seemed like you sitt to high.power was nice for a four stroke. Third since he owed his bike he had to rebuild it 3 times more than i did my shee in the same time frame. plus i can split my own cases he has to have somebody do it or go buy the tool.here are some parts he had to replace , 3rd,4th gear, clutch basket, timing chain, timing chain slides, pitson, crank,rods,bearings, and last but not least valves. and thats another thing you have to adjust the valves ever soo often, and sure its not that hard.But if you do fuck it up say bye bye valves after that piston smashes into them.