I have a set of swing arm extensions for sale that I got from Ryca years ago. They are steel and measure 10x53x118 mm and are shaped to slide right into the rear of the swing are. All thats needed is to dress the end swing arm to ready it for welding these pieces on.
wt: 1 lb 6 oz
They add 70mm of extension to the swing arm.
Ive got some computer issues so not photo here yet. I am able to email a photo if you want to see them.
I googled "swing arm extension by Ryca Motors" and it brought up an old ad on Amazon with photos, before and after welding.
I think this is it.
https://www.amazon.com/Motors-Extended-Swingarm-Suzuki-Savage/dp/B00WFDYIY4$50 + shp.