I also used to modify older bikes and cars for that matter ,I'm just glad that Yamaha do such a good job of making their bikes go so well
small areas can be improved a little but they are dam good out of the crate,
Well good luck with it I saw your post featuring the modded back end on a 600, Does look nice.!
Speaking for myself ,This time round in my biking career "The 3rd" I'm just enjoying bettering my riding skills and being constantly amazed at the levels of all round performence offered by even a mundane bike. I never got chance to better my riding in the 70's as I was constantly repairing or scrounging bits to repair the last disaster! Keep us posted on progress1