It is a fine project. The good news is that many of the Yamaha parts of thet vintage are easily adaptable. The seat can be replaced, get rid of the leading axle front forks with something bigger and in line(Seca 750 or 900), get an 18" rear wheel(Seca 650 or 750 or 900), 4-1 pipe, Some longer, better rear shocks, change the bars, etc. you get the picture. Shop around on E-bay and ask some questions.
Ken
AHRMA 412
Vintage racing - old guys on old bikes
Ken
AHRMA 412
Vintage racing - old guys on old bikes