KYMCO XCITING S 400 Manual page 128

3. Engine > Cylinders and Pistons
Also clean out the ring grooves. You can use an old ring to scrape out
any carbon build up in the grooves.
Inspection
The cylinder and piston must be replaced as a set. There are two sets of
cylinder and piston combinations. Make sure to have a No.1 cylinder with
an "A" piston or a No.2 cylinder with a "B" piston.
Mark Piston O.D. (mm)
A 83.99 – 83.98
B 84 – 84.01
Mark Cylinder I.D. (mm)
A 84.00 – 84.01
B 84.01 – 84.02
3‐50
XCITING 400i