Originally Posted by MortimerSickle
If you want a scan of the wiring diagram for a 1979 model, PM your email address to me, and I will send it as an attachment.
As for the 21" wheel, you might want check out what that will do to your steering geometry. Period articles said that going to the 23 incher was not as simple as just changing wheels. They said that the geometry had to be changed to make it handle properly. I am guessing that using the 21 without changing anything else will be much like raising the forks in the clamps.
I've got a XR600 front end I hope to win on ebay now. It's a bolt on job from what I found out.