1979 rm100 crank bearing shot

A special press should not be required. Heat the split case half in an oven 275-300d/F the old bearing should almost fall out. Keep the new bearing at room temp and it should almost fall in. Use a hammer with a large socket to finish the job. BTW change out the other side too!.
OD

I have been rebuilding 2-strokes since 1969, never used a press to reassemble cases. :blah: Jap product cases are so precise (even the early ones) all you need for reassembly is heat, and at the most a soft hammer or a block of wood (2x4) and a steel hammer. Another heat method used by many techs is to put the cases on top of a kerosene heater, heat them until spit dances on the aluminum. Keep the crank assembly at room temp.
:coocoo: Some people believe you should "freeze" the crank assy. too. but this causes additional problems as the temps of the mating pieces accelerate the reduction in clearance often way too rapidly. Most Suz's go together very easily (KX's,KDX's -diff. story) often with all pieces at room temps. However a modest use of heat on the exterior mating units works best. :nod:
OD