25mm or 30mm on a 180cc runner?

hi everyone, ive been searching through all the forum for this question and i havent found one. ive noticed most of tuned to the max runners are using the 25mm delorto and havent seen them putting a bigger carb like 28mm, is the 25mm really the best size for 180cc runner? what would be the difference of a bigger carb? please anyone enligthened me on this. thank you in advance and cheers to all.

I believe the 25mm carb is a good match for the standard inlet on the engine so you can fit it and set it up easily.

A 28, or 30mm, carb will fit but it will be too big for the standard inlet, ideally you would need to make the inlet bigger to match the carb.

hi thanks for your reply, the inlet your referring is the reedcage inlet right? if im not mistaken there are big manifolds being sold in sip and these are for 28mm and 30mm carb and its a bolt on meaning you dont have to mess with the reed cage inlet. actually i installed a 28mm oko and a malossi manifolf that is for 25mm carb ,if fits alright and runs great but i just dont know if 25mm is much better. cheers mate