Another Piston Size Question - "B" Piston in a "C" Cylinder?

[jwherb]

When I did a top end on my 05 YZ250 last summer I ordered a piston kit from NCY and put a "D" piston in my "C" cylinder (cylinder is in great shape and spec measurements).

I decided to give TTalk a try and ordered a piston kit from them. I even sent them an email specifically requesting a "D" piston. Sure enough I was sent a "B" piston (and TT's kit doesn't come with the top end gasket kit either). 👍

I've read past discussions on this topic: I know the measurements are so minimal anyway. But should I send the thing back and request a "D" and/or just get my money back and go with the NCY kit? Or would running the "B" piston be alright?

Thanks guys.

[nealy578]

I ran a b in my cylinder and it was noisy and slapped, personally i would only run a c or d in your c cylinder. I always the oem d or the largest size in aftermarket brand if available.

[jwherb]

Thanks. I'll just send it back or see if the local guys would swap it out.

[obrianmcc]

Refresh me here....How do you know what cylinder you have? I did a top end this last Fall and I don't recall anything about A,B,C,D cylinders....

[mtdirtbag]

On the intake side of the cyl just below the intake will be a ink-stamped letter denoting the cyl sizing.

[nealy578]

Mines washed off but was told if you have a worn bore you should use the larger to stop piston slap etc...