i have recently put a biturbo on my 77 maxi. and now i have an itch for speed. i have a 15mm bing carb on there already. i think i would like to keep it, but am not sure. i want to put a 70cc kit on it. but most of the ones i have seen won't fit the bing. should i just upgrade to the amal 17m. what do you guys think what should be my next step in kitting out my bike.