Yamaha YZ125 combustion chambers

Chamber selection:

2005+

FX11 - 8.3cc Stock
FX12 -  7.8cc (95+ octane) 
FX13 - 7.2cc (100+ octane)

1994-2004

Y11 - 10.0cc Stock
Y12 -  9.3cc (95+ octane)
Y13 - 8.8cc (100+ octane)
Y14 - 8.1cc (105+ octane)

OE cylinder 144cc 58mm

FX144 - (91+ octane)

FX145 - (100+ octane)

Athena 58mm 144cc

Athena144 9.8cc (91+ octane)

Athena145 9cc (100+ octane)