Myself and "OND" have 1961 Briggs Photos posted @ OldMiniBikes ,but the carb setups are different, mine is updraft and his is not, both serial #s begin with 61, I searched OldMiniBikes Photos for 1964 Briggs and it shows a 1964 and 1972 with updraft carbs? What yr did Briggs stop using the updraft carb ? We are a bit confused, any help would be appreciated.