compatability

Hey guys, I've been roaming the threads trying to get as much info as I can for a 650 front end swap. (I'm planning to use the dual front disk setup and like the larger tube size.) But the one thing I have yet to know for certain is which bearings to use. I currently have a set of 650 forks...

I've had a hard time deciphering the differences between some of the older wiring harnesses. I have a 1981 XS400 that I'm rebuilding and have had a helluva hard time finding a new wiring harness (lack of time, not laziness, has been my foe). I've easily found harnesses for the 650's of that era...

I just bought a 79 xs400. It's my first bike and this is my first forum post and I'm a total rookie at all of this. The bike has no rear master cylinder. I've been searching all over for one from a 79, but could only find one for an 80 xs400. Does anyone know if this would work? If not, any...