PRO-X piston help!!!

[tishma09]

i just resently tore down my 85 atc 250r that i have had for 6 years now and i cant seem to find what size the piston is, all that is writen in side of it is prox HM25084, japan. and the number stamped on the top is 50 can any one help me out on wat it is. I really would appericate any help yall could offer

[SWIGIN]

sounds like its .050 over

[TimSr]

sounds like its .050 over

Ive never seen a piston marked in inches. Im not personally familiar with ProX pistons, but .50mm is a lot more likely (.040").

[Bryan Raffa]

if its a 50 on top its a 67.25mm thats from a pro x book for that year. I would have it mic'ed to be positive

[Bryan Raffa]

if you need another piston like you got the part # is 0399
If bore the next size up is 67.50mm Kit # 0641 $118.00

[tishma09]

thinks that is what i was lookin for i had never herd of a .050 over piston so i was just checkin