Ted,
You probably know this as you have been in Africa as well but if I summarize what i remember from Africa is the actual CdP costs about Euro 200/250,- for a 25 page CdP. Maybe a 10 pager (or less if available) may be cheaper. That is out of pocket money you wont get back.
What we did for Africa is actually transfer the bond ($6000,- or so for Egypt) into the acount of the automobile club, which we received back without ado after sending in the completed CdP upon our return. That was all straigh forward.
The cash bond however that you have to put up for Iran is very high. To avoid transferring cash money into the automibile clubs acount you can provide a guarantee or letter of credit from an insurer or bank. From the link you referred to, I make out that the bond for Iran is some 250% of the bike + gear vallue. Your Honda should be valued no more than $1000,- albeit a 'as good as new' bike due to the rebuilt but the age works in your favor, plus (max) $1000,- worth of gear. The bank/insurers bond/guarantee typically costs 1.5 to 2% of the bond! If the bond is set at 2.5 x $2000,- for your bike you would be looking at total cost of some Euro 300,- for CdP + bond cost!
Then again, you would save that money again in Iran because everybody seems to wanna invite you for diner over there
The amount stated at the CAA site seems a bit over the top to me! If that is what it is then I agree, $ 750,- carnet cost for a $1000,- bike is not acceptable!
Anyway, i think it's worth investigating possibilities to combine at least part of the trip and possibly join up after Iran again, or indeed skip Iran altogether. I'm waiting for a reply from Leonardo.
Cheers,
Noel