never the less the keihin sight has 4 different ways to measure your carb to distinguish the size it is. And they actually go by measuring the OD and matching that up with there chart. the only catch is the only real difference according to there chart is a couple mm of difference in the whole height of the carb. Which I have found really hard to do with a metric tape measure(accurately). I called the guy at sudco and he told me to measure the ID of the hole and I measured 34mm not 33 and not 35. Fuck the metric shit to much room for error.