I just got one from spookytooth..and it isn't 3mm bigger as they say..I'll go remove it off my bike and measure it right now..The slide measures .589 (14.9mm) I couldn't go by my carb on the bore size because I've already reamed it out, but I'd say they are 14.6-7 mm, so you gain about 1mm in carb size. I taper bore them out for better flow. I just tried to download a pic but they said it was too big. Here's my email
[email protected] I'll send you some pics of it. I'll sell it for the price I just paid for it if you're interested, because with my mods I really need a 18mm.