Moped Army

i have been looking at kits allot lately and was interested in the airsal 70cc 45mm kit, i had read allot about not being able to fit the skirt into stock cases with ease and was wondering if anyone has done so with the 1.5 e50. on that note what is the fundamental difference between the 1.5 and 2? i currently have a 15mm bing which seems large for my set up; is this carb to small for a kit? thanks for the help