RE: starting my kfx 400
Yes one thought, and I almost hate to suggest this, you might have low compression. I'm not familiar with your machine, but back in the day I bought an 1985 Suzuki Quadracer, two smoker, and I got it home and it would not kick start for anything. I pulled it with the truck and it would finally start, but as soon as it was cold again I got nothing. Finally I got fed up and took off the jug and found a hole in the piston about the size of a bb like as in a bb gun, it didn't have enough compression to fire with just the kick, but I guess pulling it would cause enough to get it to fire. Now in your case if it's a 4 stroke with valves, you might have one that is sticking, or burnt. Good luck, but that is the only thing I can think of. Oh wait what color is the spark? If its yellow then its weak and it may just be the coil. Good luck man.