Yes, but you may find that any size larger than 7mm will be a tight fit inside the hole in the CDI box. You may need to trim it down only in the portion where it fits into the CDI.
I do not like to use a razor blade for trimming, it leaves a too irregular of a surface and it should be a water tight seal. I use a belt sander but a grinder will also work. Smear a thin coating of silicone paste (sold as GB Ox-Gard in home improvement stores, electrical section) on the sides of the wire and twist the wire onto the screw inside the hole.