At only 1.25" you should not have to change any cables or hydraulic lines. At 1bout 1.75, things get a bit more challenging, especially with the "choke" cable. Murphs' Kits does sell extended cables and lines. I went with an handlebar adapter to fit standard bars, wound up using a Yamaha ATV bar, as recommended by SiSF. The clutch was OK with a bit of "custom" rebending, throttle cables were re-routed, the choke cable and brake lines(two hose stainless) were longer lengths from Murphs'.
Have fun Farkle-ing.