Installed heating elements to original grips. It took a while to install them, because I wanted everything hidden. It also needed thinking how I can pull wire to element to the throttle grip from the bar.
Clutch side is easy; just install the elemement, a small groove to ”light switch housing” for wires and pulling the wires away inside the original wiring harness.
Throttle grip had to be removed from the plastic part. Then removed element original wires (they came from wrong side/direction). Measured how long is the bar end weight (in my case the outlaw cruise control). Then drilled a hole for wires. Marked from the hole to the bar how much throttle turns.
Made groove to the bar, so the wire doesn’t touch the bar in any throttle position. Made hole to the bar so wires can access throttle/kill switch body and from there pulled the wires inside the original wiring harness.
I also smoothened the small grooves from throttle handle plastic to make the element film sit better.
Electricity I stole straight from fuse box from blinker fuse. It is fused with 10A fuse and heater has 5A fuse. I thought that 10A fuse should last because blinkers are randomly on and Katana has led blinkers. I also thought that if the fuse blows for some reason, then living without blinkers is less critical than for example headlight etc.
Attached some pictures.
I did it this way because I like original grip touch and thickness and also don’t want any additional wires sticking from the grips. Of course the control panel is visible and cable for it.