on my bros 86xr80 all original never rebuilt the piston at the bottom cracked n broke off. i have all the fragments but i dont know if this is the reason it was running bad. it stalled and wouldnt stay running but i could bump it n get it goin but it would die w/o gas. i though the crank was toast but i just checked the rod side clearence and it checked out great. i have a few pics but i dont know how 2 put them on. can someone expalin?