There are charts on ohiocaferacer's (a member here, or at least was. I haven't seen him in quite a spell though. might be too busy with his business) site online (ohiocaferacer.com) that include the fork tube sizes and tripletree stem size of a lot of motorcycles. might at least give you a starting point. biggest thing I know to tell you, though I have only seen it done, is that the triple tree stem can be removed from both the stock tree and the one to be used, put the stem from the stock tree, into the tree to be used, weld or have it welded in place and then the new tree can be installed on the current bike. Of course, some forks will change the rake and trail (I think that is what I have seen discussed on here, on the rake and trail. All I can offer is some tips, someone else, with actual experience needs to chime in here and give the needed info. But, an example is I have a complete fork setup, with the brakes tubes (38mm tubes), built in fork brace and air assist, on the tube/leg assys, & triples from a VT750 That I am wanting to put on a build and I have found that the only difference in the tree, is the stem might be a little longer on the VT part. So, I should be able to swap out the stems and be good. At least, that seems to be all. several different fork assys have been used, but one that comes to mind is the GSXR unit. And Greg (ohiocaferacer) used one on a CB350 racer he built and I think he detailed it on his website and maybe on here. Lot of wording here, but I don't know if it helped any. Hopefully it helped, at least some.
Now, I see that TJTalan posted while I was typing. Great.
