Suzuki RM250 Phathead combustion chambers

Suzuki RM250 Phathead cylinder head kit 2003-2009  

Chamber selection:

Y21 - 21.1cc Stock
Y22 - 20.1cc (95+ octane)
Y23 - 19.1cc (100+ octane)

Suzuki RM250 Phathead cylinder head kit 2001-2002  

Chamber selection:

S31 - 17.6cc   Stock
S32 - 16.4cc  (95+ octane)
S33 - 15.5cc  (100+ octane)
S34  - 14.4cc  (105+ octane)

Suzuki RM250 Phathead cylinder head kit 1996-2000

Chamber selection:

S21 -  20.6cc   Stock
S22 - 19.2cc  (95+ octane)
S23 - 18.2cc (100+ octane)
S24 - 17.6cc  (105+ octane)