Is my yamaha blaster piston stock?

[timex69]

hey people
is my piston stock all it shows on the top is an X and an arrow and underneath the part number is 37F01, written on the inside is a 3 with 3 lines over it and the letter S and on the outside it says ART..please help.

[smokinwrench]

I would say it is more than likely stock. ART is known for being stock. Most people when they bore out a machine they go with Wiseco or ProX. Most pistons have a size stamped in the top of them. (0.010,0.020,etc).

[timex69]

ill have a look man thnx