I believe the backshifting is primarily the job of the secondary clutch. This duty would be performed by the helix and spring in the secondary. Different helix's and springs produce different backshifting results. They also have roller secondaries which offer much smoother operation. I'm not sure if the secondary clutch on the Ryker is a roller secondary? The point however is.......many of the clutch characteristics are adjustable by changing the weights, springs and helix. Most of the time from the factory the clutch is setup to give you the best performance over a broad range of RPM. You can tune the clutches though to give you faster acceleration, more or less backshift, etc. When you tune for a specific parameter other parameters suffer. As an example if you tune for faster acceleration you will lose top end speed.......if you tune backshifting for better coasting you'll lose quick pickup if you punch the throttle The clutching adjustment also has to work within the parameters of how the engine builds and delivers power. That's why typically a clutch kit is tied with an ECU flash.
I'm no expert in any of this. It just stuff I've picked up after years of snowmobiling. It's complicated for sure. There are many companies that offer specific clutch kits for snowmobiles so riders can tune their sleds the way they like. The same could be done for the Ryker Here are some for the 900 Ace
http://www.hotrodsledshop.com/skmxz900acec.html https://shop.rvsperformance.com/ACE-...CK-ACE-900.htm