There's a ton of mods needed to change an XS11 to chaindrive, for the swingarm there's heaps of modern swingarms out there you could use, just need to sleeve and spacer their pivot point area to slot into the XS frame, XS11 pivots are 300mm apart, pretty much all swingarms are sized around, say, 220mm - 260mm width at the pivot points. If sticking with twin shocks, on most alloy swingarms you'd need to weld on lower shock mounts too. The front drive is the tricky bit, the front sprocket drive on mine is home-made, a cut-down original XS11 drive unit, works perfectly, but once the swingarm and drive unit are sorted there's still a thousand other things to do to get it all setup and running kosher
