So I Finnaly got around to pulling my 72 lt2 apart and when I was looking at the cylinder i saw that it was shoot. I was looking at the some on ebay and found a good looking one that was labeled as oversized. I asked the seller more about this part and this is the responce I received.

"YES YAMAHA MAKES 4 PISTON SIZES SO ITS ON THE FIRST OVER STOCK SIZE SO IT CAN BE BORED UP 3 MORE TIMES"

Will this cange the CC of the bike and will I need to change the carb if I go this route. I am new to this and really would like to see this bike run again.

Thanks In Advance

 

You wont need to change the carb, it's a pretty minor difference in displacement. You will need to have the cylinder bored and honed at a machine shop. In the ideal world, a local one will have experience with two strokes; take the cylinder in and they'll be able to measure it and tell you how much work needs to be done on it, if it was really beat up they may have to jump to the second oversize to clean it up. Local is nice because once they do the measuring, you can order the correct size cylinder and bring it to the shop so they can get the tolerances dead on with the piston and cylinder in hand.

If they are not experienced with two strokes, they can still do the bore and hone, but you'll have to request they chamfer the ports or read up on how to do it yourself.