03 Cr 250 Wiseco Pistons

[sandflyz]

When ordering a Wiseco replacement piston for an 03 CR 250, do you just order a piston for a standard bore size. Its time for a new piston for my bike and the piston has never been replaced in it. In my owners manuel it says when buying a piston to make note of the letter stamped on the outside of the cylinder. Mine is an "A" size meaning i need to purchase an "A" piston to replace the original. The problem is that when I look at the Wisco website it shows a STD size, and then 4 or 5 additional oversize pistons. It does not show an A-B-or C like the manual shows. How do I know i'm buying the right size for my particular cylinder?
One more question. is my cylinder bore made of Nickasil?

thanks
anyone

 

[+30]

grain of salt

I have been using wiesco pro-lite pistons since bike was new, and have asked the weisco rep the same thing at an amateur event one day, and they told me the a,b,c jugs difference is not a problem with using a standard size piston, keep in mind you may have to drill two holes in your piston per the instructions included with the piston due to the thin easily overheated exhaust bridge in your cylinder. take this all with a grain of salt though, Im not engine expert....

 

[Gibby]

The A,B,C thing is just for the factory pistons matching factory cylinders. The wiseco pistons fit all three. The reason why is because the there isn't much difference and the wiseco pistons tend to swell as they get warmer. The only time you would have to go bigger is if you bored or sleeved it.

 

[ellandoh]

if you're really worried just hone the cylinder if necessary measure it and order a vertex that fits within specs. they have any size you want a,b,c,d, etc thats whats in my 03