Kehine Jets go by a different number system. Basically compared to Mikuni a 300 Mikuni would be about a 150 Kehine. Pilot Jets are opposite. 25 Mikuni would be a 50 in Kehine.
If you are sure that Kehine Jets fit, get ahold of Jets are Us they should have a chart showing diameter of both and be able to cross reference between the two.
What size does your current jet say ??