Cotopaxi N.P.
 

Cotopaxi N.P., Ecuador South entrance no longer allows motorcycles to enter park.
Due to local cyclest caught hunting in the park.
You can hire a car/guide for $60.00
NO THANKS
Not sure of North entrance.

I also heard from a friend here in Quito that both entrances dont allow motorcycles anymore.
I think you can go up Chimborazo though.
I'm going to try to ride up Pichincha tomorrow. Not sure if there is a rode/trail.
Thanks Billy for the update