here is a quote and pics from my last drilled bing. dont go this big, its the biggest i have gone before and i havent run it yet.
"heres the whole thread":https://www.mopedarmy.com/forums/discuss/read.php?f=7&i=85725&t=85662
"i took a 12mm bing, ate a bunch of the meat with a tungsten bit on the dremel. then i clamped that shit down, and inserted a fucked up big orange grinding bit for the dremel. it has been used on lots of other projects so it was already in the shape of a cone. so i literally barely held the dremel over the carb body, and just let gravity do the work. listened to some music, smoked a cig and sprayed wd40 a shit ton. it came out soooo even and smooth. cant seem to take a good pic though.
i didnt hit into the float bowl or anything. i stoped just short of the slide chamber so technically its like 16mm on the air filter side. i just wanted to make sure air didnt get past the sides of the slide. the main jet emulsion tube has a groove added to direct flow to the intake manifold side. and i will be sure to do the "lil buddy" trick and drill a small hole on the side of the carb above the top of the tickler button. this allows a minute amount more air in at idle which helps with the richness in low rpms notorious to the bored bings.
the intake was fun. i used a franco morini stock header (which is 20mm) and reshaped it to fit at the right angle. i then cut about 1 inch off an existing stock 12mm intake, sanded down the skinny part till it slid right in to the negrini header. applied jb weld, let cure then bored with the same method.
im very excited to see how this setup performs. i really really would like the monza to be a daily driver, but shit, any motor thats reliable is too slow for such a fast looking bike. any motor fast enough to match the looks blows up. e50s wont work, i have to modify a za50 to even use that. the original motor is rare, expensive, and the dollar is fucked right now. so this should be the best of both worlds. hoping for like just under 50mph. good torque, keep up with traffic and… not blow up….
heres the pics! big but not too big.