Re: 143 Speeditwin year Home › Forum › Ask A Member › 143 Speeditwin year › Re: 143 Speeditwin year RICK EICHRODTUS Member - 2 YearsReplies: 267Topics: 79 March 26, 2018 at 2:17 pm #73060 My best guess is that with a low serial number of 364, your motor would have to be a 1929 or 1930. I know this is not much help but at least it narrows it down some.