Motorcycle Repair: 2003 blaster piston, yamaha blaster, sure what size

Question
I just bought a 2003 yamaha blaster and it needs a piston. Im not sure what size i need as the old one was thrown out by owner. All i know is its bored 67.5 over. Any idea? Thanks

Answer
Heather,the blaster came with a stock bore of 66.00 mm so it has been bored to a larger size. The maximum bore size can be 68.25 mm. Wiseco makes a pro-lite piston that big but have have the bore measured front to back and side to side top and bottom to make sure there isnt any strange wear in the middle of the cylinder where the piston rocks in its normal travel.