Sparkplug thread diameter - Nighthawk 750

[beardking]

Can anyone tell me what the sparkplug hole diameter is on a 99 Nighthawk 750? I have a colortune plug that I'd like to use for tuning the beast, but it's a 14mm plug (threaded part) and it's a bit too big. I'm thinking the NH is 12mm, but I wanted to see if anyone else knew before I went and ordered the adapter.

Thanks in advance,
Beardking

[thespirit]

12mm