What year/years had a front sinlge disk and dual disk break?

I was just wondering what was going on with break setup on the 650 Maxims. I keep seeing some with a single front disk and some with a dual front disk setup.

 

mine is an 82 xj650j and has the single. I believe the LJ and RJ models had dual and maybe the turbo???

 

Re: What year/years had a front sinlge disk and dual disk br

1980 Maxim had single disc.
1982 & 83 Turbo's had dual disc.

 

How much hassle is a dual disk swap? Is there a write up somewhere about making this change?

 

I think (and that's think) that for the 650's they all got the single front, except for the Seca's and the Turbo's that got duals.
Pretty sure all the 750's got the duals, and you can swap front ends too if you really want to.
Having said that, even with the single front disc you'd be surprised how big an effect just changing out that old rubber brake line for a modern braided-steel covered teflon line will make! Add some good pads, and that single caliper can grab pretty hard!

 

Euro XJ650 models had the US XJ650RJ Seca dual discs..........

The swap to a XJ750 Maxim or Midnight Maxim (but not 750 Seca) front end is pretty straight-forward if you acquire ALL of the parts from a donor bike: chrome fork tubes, lower tubes, steering upper and lower brackets, calipers, rotors, master cylinder, and distribution block (if you re-use your XJ650 lower steering bracket, you can keep the same dist. block and use a double-deep union bolt on the outlet side, just as Yamaha did on the 1983 XJ750 Maxim models. The 1982 XJ750 Maxim used a long "log" type distribution block which will not fit your XJ650 lower steering bracket). You will have to re-use your 650 upper steering crown bracket to accept the 650 handlebars properly. Plan on rebuilding everything (master cylinder, calipers, forks) before you install it! If the rotors are warped or gouged or worn below their 4.5mm wear limit, I offer replacement upgraded rotors for these models. While the front wheel is off is a great time to replace the front wheel bearings, too.

And while you're doing all this, this would certainly be the easiest, and thus most ideal time, to replace the ball-bearing steering head bearings with the later-style tapered roller bearings.