hey guys and gals, my names Mike, from Vancouver island Canada. I just got a 2004 speedmaster that has been in a small fender bender. Looking to put a weld on hadtail and a springer on the front. Anyone ever done this? Anyone know what the size of the neck is on this bike? Anyways stoked to be here and get involved in the community. Cheers
Welcome to the Asylum you should fit right in. Too keep the inmates happy we will need photos .hope it's black Tucker
Welcome from another new member. Sounds like an interesting project and everyone would love to see some pictures of the progress. If you are asking about the diameter of the headstock, you might be able to just locate the correct bearing numbers and then look at the manufacturer's specifications to get the precise diameter. I just looked at a part diagram for your headstock. It appears to have 2 different bearings. You should be able to cross reference it to an aftermarket bearing part number - something like NSK or Timken. If you Google that part #, you will locate the factory specs. I used the diagram at https://www.bikebandit.com/oem-parts/2004-triumph-speedmaster/o/m82137#sch566439. The bearings are #25 and #26 and appear to be different sizes. I think the numbers in the parts list (e.g. 30,50,17) are id, od, and thickness of the bearing, but I'm not certain.