It is possible to reroute the brake hose. I put a total of 8 inch risor on. The only items that needed to be replaced were the throttle and the choke cables. If I remember right the brake hose is routed behind the coolant jug. It is easier to fill coolant than bleed brakes. Take the jug off and take off other tie downs and there is enough to run the hose. If you go any taller than 8 inches you will need a new hose.
I went out to take picture but it can not be seen very well in picture. 3.5 inch risor, the brake hose does not need to be replaced, just rerouted. With a 3.5 inch risor the throttle cable for sure needs to be replaced. As for the choke cable try it, if there is any binding replace it. Hole this helps.