i havent posted on here for years but i figure some one can help me out.

its not a quad, i got a 92 cr125 with a blown topend. im going to rebuild but i dont know the current bore size. im guessing i need to take the jug off before i can order the right piston kit but tell me if im wrong.

how do you identify the bore size? is there piston markings or numbers some one please tell me whats up.

thanks

 

use a mic. on it.

 

some times the top of the piston at the center might tell you what bore it is, you will have to clean the carbon off for any chance of reading it. If the piston is warn out you may have to measure the bore rather than the piston, if you do measure the piston, measure at the bottom of the skirt, new bore should have around .004" clearance, maybe a little less for a 125.