2001 yz 125 motor swap

Hey guys I could use some help here. Long story short I have a bad motor, breaks in the case by the water pump (looks like the last owner jb welded a a piece back together and it failed) anyway, the year is a 2001 yz 125. I’ve had the bike a year and a half and never got to it. The crank bearing spun and the crank is stuck. I’m sure I could split it with enough effort but for now I want to just buy a new bottom end with a good crank and bolt my 2001 head on. 


Im aware of different shaft lengths and pistons on closer years but I can’t come to a conclusion on which years would be good to match up. If I could just find a 2001 bottom end I’d go for it no questions asked, but of course it’s hard to find an exact year. I see a couple 98s and 2002 bottom ends for sale. The real question is what years are compatible where I could just bolt my top end to another year with little to no modifications? At this point I want this bike gone for the space. I have 4 other bikes so some shelf space would be nice! I would really appreciate some feedback. Thanks 

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