Fxdb-d engine sprocket removal,tried heat,still can't shift

That isn't good. There really isn't anything further to try. Not knowing how hot you got it or how much force you're putting on it I can only suggest trying the same things again. Let me first make sure you know it is a standard, right hand, thread. Turn it counter-clockwise to remove. The clutch hub nut is a left hand thread but not the crankshaft sprocket. It takes 400 *F to soften "red" threadlocker so make sure you're applying enough heat to work. Also it takes about 350 lb/ft of torque to get it moving. That's a lot and is hard to apply. If you're applying this king of heat and this kind of torque and it still isn't moving then I'd say the bad news is it may have a thread issue. The only option left is to grind off the head, remove the compensator or sprocket and then then grind down the threaded shank until it is thin enough to split with a chisel and then it will come off. I hope this helps. Thanks, P.J.