Suzuki DF25/DF30 Four Stroke Service Manual, Page 167Get this manual
7-50 POWER UNIT CRANKSHAFT MAIN BEARING Check bearings for pitting, scratches, wear or damageIf any improper condition is found, replace both upper and lower halvesAlways replace both bearing halves, never only one half of bearing setUpper half Lower half
CRANKSHAFT JOURNAL OIL CLEARANCE Check clearance using Plastigauge according to the following procedureNOTE: Assemble each bearing in its original position before checking clearance(1) Clean surface of bearing holder (crankcace, and cylinder), bearing, and main bearing journal(2) Install main bearing to cylinder and crankcase