So I picked up an 03 KX65 (actually its really an RM65 but same motor) with very low hrs and 165psi compression a few months back for my 10yr old son. I knew these 65's had issues with cranks going out so I had planned on replacing the crank this winter. Well we didn't get that far. It blew this weekend and took out the Cylinder, Piston and head. The Head and Piston are completely toast and the cylinder has 2 deep scores and I'm not sure it is salvageable. I ran Amsoil Dominator @ 40:1 and Belray Gear saver in the case, changes every 2 rides.
Now I'm stuck not sure what I want to do and could use some advice please.
Option 1 - Found and complete motor for 750.00, for what its worth it's supposed to have about 10 hrs and came out of a very clean bike
Option 2 - Rebuild the top and bottom end, with new Cylinder and head Piston kit and crank kit for about the same price, me doing the rebuild.
Option 3 - Found a KX65 full bike looks clean (haven't seen it personally nor check the compression) for 850.00
I feel like with option 1 and 3, I'm going to want to replace the crank soon anyway so I know for sure the condition of it.
For those of you with 65's how are you staying ahead of this issue. Are you pulling the top end every 5-10 hrs to check the crank tolerances or what.
Is there a crank kit that seems to last longer than others?