I've been reading about your cb125 and planning to do the same on mine. Won a bore up kit on ebay and now there is an XL head on ebay. But since this head is marked by 381 not 383 I'm wondering if it has the bigger valves and ports? The seller said the intake port is 30mm and mine (one-piece head) is 27mm.
Could you verify the diameter of your head?
Kind regards from Belgium,
Dave (dave_wauters@hotmail.com)
