My 2007 kx250f is giving me problems, Its a B!tch to start and it has no low end what so ever. I had a buddy check it out and he thinks its the valves, it has 55 hours on it and has the stock valves and I have about 4 rides on it since the valves were done last. Would it be a wise choice to throw a set of stainless valves in it?( i'm still kinda new and dont know a whole heck of alot about these things) Also when I started it it burnt a little cloud of blue smoke. Any help would be greatly appreciated!