Yamaha YZ125K piston marked S is this a std piston

[oldyzman]

Gday,
I have purchased a Barrel and piston from US, they cannot measure the bore but did say that the piston was marked with a S, i am thinking this means std size (56mm). i want to confirm this so i can order a 1st oversize piston kit and get that on the way too. ANy thoughts
OLDYZMAN

[jimg1au]

BRETT
looked on the usa parts site and they only show std pistons do they have chrome/plated bores

10    24X-11630-00-00 PISTON KIT STD (STD)   1   
        39W-11630-00-00 PISTON KIT STD (STD)   1
 
11     24X-11631-00-95 PISTON STD (24X-11631-00-93)   1   
         39W-11631-01-94 PISTON STD (39W-11631-00-95)   1 
 
12        5X4-11611-02-00 RING, PISTON   1   
13        137-11633-00-00 PIN, PISTON   1   
14       93450-17129-00 CIRCLIP   

[oldyzman]

Thanks for your help Jim, the cyl i broke has cast iron  bore there seems to be some oversize 24x... pistons available, maybe just wait for the cyl to arrive. I just seem to recall seeinf an S marked on top of a std piston maybe off my 2002YZ
Cheers Brett, have a good weekend...

[Freakshow]

measure it

[oldyzman]

Freaky, the cylinder and piston was on the way from US. I wanted to pre empt size and order a piston in advance so i could get it all at nearly the same time. The dood selling it could not measure it. Any way its here now and is std...
Cheers Brett