Doing an 87 250 for a customer, claims it went from running fine to running fine while burning a metric fuck-ton of oil. Confirmed upon receiving. Planning on it being rings, have yet to crack the motor open. Have removed some plastics, the tank, air box, Exhaust and carb. Is there a trick to doing the top end in the frame or do I have to pull the motor? I usually do sport bikes or standards so I'm a bit out of my wheelhouse.