The cheapest way to increase the compression ratio on the CBR300R engine is to replace it's piston with the one of the earlier CBR250R.
In order to maintain the same compression ratio of 10.7:1 on the CBR300R like on the CBR250R, despite strocking it by 8mm, Honda flattened the piston top of the new version. Simply by switching it with the piston from the earlier model will therefore do the trick. (same cylinder used but stamped 286cm3 instead of 249cm3)
In order to maintain the same compression ratio of 10.7:1 on the CBR300R like on the CBR250R, despite strocking it by 8mm, Honda flattened the piston top of the new version. Simply by switching it with the piston from the earlier model will therefore do the trick. (same cylinder used but stamped 286cm3 instead of 249cm3)