Maybe a windshield would fight the" it is too cold" excuse.  
Oddly, perhaps the Bonnie doesn't quite suit you like the Savage did?

Well, you have identified the issue; the easy solution is to throw a leg over  Bonnie and ride- don't think about it, just do it.

Good luck with it.

Well, if you need some motivation, maybe this will help. Some of us can only DREAM that the temp is in the low 50's. That's perfect riding weather around here.

http://www.weather.com/weather/alerts/localalerts/l/14623:4:US?phenomena=WC&s...

I ride all year round. Here it gets down to the upper 30's in the evening in December and January.
For cold weather I use:
- Tourmaster jacket ($200)
- Tourmaster overpants ($150)
- Hybrid, full face  helment ($200).
- Pinlock fog shield ($50).

On my winter bike, a Suzuki DL650, I have hand guards (a big help) and heated grips (I only turn them on when it's below 45 degrees).

The windshield makes a big difference. When I put a Plexifairing on my Savage, that alone made me more interested in riding in colder weather. (It sucks when it rains - no wiper). Now I use a chest level shield, and with the full face helmet, that keeps me warm and mostly dry. I can wipe the rain off my visor with my thumb.

I gave my car to my daughter, so far, I haven't missed it much - it would be nice to have a place to put my coffee, and I do miss the windshield wipers.

So many of life's little issues just melt away when riding. It's such good therapy... and NOWHERE is it more called for than in your case.