I have a 25mm, $30 Japan made carb on my 125cc ATV auto w/ reverse. It came w/ a 20mm and small intake, I put the 25 on a 26mm manf. and gold swivel plate. I have a 26mm Japan made Mikuni here I put on my 107cc X18, to much air, took it off after 2 hrs. Got a 22mm on it. The blue finned CDI and orange hp coils work good also.