i bought my son a 89 blaster a year ago. i took the top end off the engine and on top of the piston it has an X stamped on it. does this mean its still stock bore?

 

I don't know how manufactures marks their standard original pistons. I do know theough that all replacement pistons are marked with the dimensions of the overbore IE: .010, .020 Etc or in millimeters. Clean the top of the piston real good and look if you find any such marks. If don't find any and you have a manual & some dial calipers, measure the outside diameter and and you should be able to determine the size. If not take the piston to a machine or service shop and they should be able to measure it and tell you if it's a standard bore (size) piston or not.

Rude Dog

 

My stock bore Nix`s pro-x piston has a x on the top if i am correct the x stands for the exhoust side of the piston

 

An X on the piston does indicate that it is the exhaust port. However, A stock OEM blaster piston does not have any markings. Most aftermarket pistons do. I would say the same as the last post. Measure it to be sure.

 

The first time i took my Blasters top end off I changed the piston. The piston was a stock one and it has an "x" on it. If you wanna make sure its stock look inside at the numbers(3f..). And it was the stock bore. So that means that you have the stock bore also.