I don't know how much it could be useful, but I know that a lot of people that travel with a motorcycle from Italy to France (or vice versa) pass from my place, so from Val Susa. In practice our Valley is the main Valley that connect Turin, the main city in our area, to France. There are two main roads:
-SS24, passing from the "colle del Monginevro" ("Col de Montgenèvre" in French)
-SS25, passing from the "colle del Moncenisio" ("Col du Mont Cenis" in French)
You can do the first part of this route (from Turin to Susa) with the road that you prefer, because the two road are parallel in that trait. Then you can choose from which side you prefer to pass the alps.
I prefer the second one, because in correspondence of the Col du Mont Cenis there is a beautiful lake. And then I'm practically grew up exploring the area around the last part of the SS25.
However both those passes are quite high (1800 and 2000 m respectively), so I would suggest them only during the summer and with good weather conditions.
You can also use the highways A32, but it is really expensive (one of the most expensive in Italy), and then the alpine passes have both a spectacular view that you will loose using the highway.
Street view of the SS24 just before the Col de Montgenèvre
https://www.google.it/maps/@44.95137...e9eQ!2e0?hl=it
Street view of the Col du Mont Cenis: -the "Gran Scala" (in French is probably "les échelles". Both the nouns mean "the stair")
https://www.google.it/maps/@45.21633...nDXg!2e0?hl=it
-the lake
https://www.google.it/maps/@45.23064...cGkg!2e0?hl=it
(the images were taken during the autumn, when the lake is half empty due to the maintenance works on the hydroelectric plant that uses the lake water. During the summer that place looks like this -->
http://www.vbs50.com/foto/fotocitta/...20Lago_011.JPG)