Hey blaster forum I've come across a yz250 project we scored it for 200 bucks. The guy said he put a stock size cylinder in the bike but the bore was bored over to a 68.50mm. I am pretty sure there 68mm stock. I think it's a 2001 also. I'm going to order a new piston kit from wiseco but I'm not to sure what size piston to order. I've seen 68.40 over bore pistons and 68.50 over bored. Which one would I get for a 68.50mm. sorry if this question sounds stupid but this my first time messing with over bored cylinders. Thanks
Yz259 question with bore sizes
- Thread starter FasterBlaster03
- Start date
These are not Blaster jugs. No boring in a plated jug. You will not only be measuring piston clearance but also ring gap on your new piston. Measure the bore top and bottom.
I have a YZ125 with a new Nikasil plated jug from Mellinium plating. Thats the way to go. They can exchange a new plated overbore with a core charge.
I have a YZ125 with a new Nikasil plated jug from Mellinium plating. Thats the way to go. They can exchange a new plated overbore with a core charge.
The cylinder is all aluminum with a thin layer of plating.if bored and replated you can go thru multiple pistons ussualy. If steel sleaved. It will wear like any other cylinder
I have a 68.50 mm piston but it doesent fit in the bore and when I measure it it only measures 68mm. The piston had a lot of play in the bore when it was together
Do you have a machine shop near by that does 2t work. Bring it there and see where your at. If they bored it. And put a sleeve. In it. It's probably going to wearout with every piston
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