if u take it apart it has to go back together correctly using a press unless the bearings are rusted ect i would clean it up i have just rebuilt a touque major 140 and the crank job i wouldnt atempt anyway over your way u can get all the bits for it at dg engines belmont piston /rings/gaskets fuel tap cork ph 92777733 ask for david regards steve.
It's a performance engine place doing it so I hope he knows how to do it haha. I'm pretty sure he can just press it out hone it and press it back in!? Am I right?
Take the head off, undo the rod bolt, remove the piston and rod. Flip the motor over, remove the coil. Remove the blade boss (its on a taper) remove the flywheel, then press the crank out. You dont need a crank, you can do it with care and a hammer.