i need to replace my crank bearings on a za50 crank, particularly on the magneto side , but ive hit a wall on trying to remove the bearing due to the brass oil drive. i dont have a puller, any trick on trying to get it free? i already tried heating it up, but stopped due to fear of damaging he threads. Also, can i run my za50 with out the oil drive? the spare crank i have doesnt have one on it.