CAN 84 AND 85 KTM 250 PISTONS BE INTERCHANGED? 84 PART NUMBER STARTS WITHH 543 AND 85 STARTS WITH 544.ANYONE HAVE PREVIOUS EXPERIENCE IF THESE PISTONS SWAP OVER? I DONT HAVE 2 SIDE BY SIDE TO VISUALY CHECK.84 MODEL SEEM EASIER TO GET IN THE OVERSIZE THAT I NEED FOR MY 85 MOTOR.CHEERS GREGG