Hey man the head has to come off because you have to remove the valves to put the seals in. I would also recomend lapping the valves while they are out. Mine did this last fall started smoking bad during start up and reving it up. I went ahead and pulled the valve cover off the head (everything) did the valve seals and lapped the valves. I also had it bored .040 over, put in a 101mm piston, new rings. Runs great now. I also put wisco gaskets in. FYI if you do a tear down replace the timing chain as well.