Kindly check with CARNET for traveling through Iran.
I believe the upfront duty required to pay when crossing Iran is 5 times that of your vehicle (Bike) value.
In order to travel into another country with your vehicle requires that you pay that country's duty on your vehicle first. And depending on that country's duty laws it can be a huge amount.
Consult the CARNET website for the chart of duties when crossing each country on your route.