Thought I'd contribute with my experiences in Syria, hoping they can be of use.
No carnet needed - Warning
Entering Syria with your bike does not require a carnet but I still recommend having one. When you enter without a carnet you have to pay a temporary import fee to the customs and a traffic insurance. The insurance is very straight forward, about 1300 s.p for a month (23eu). It doesn't matter if you stay one day or 30, you still pay for the full month.
The import fee however is not so straightforward and this is where the warning comes in.
Whatever they tell you at the border the import fee is per day and is around 10 euros/day! If you overstay the number of days stated on your temp. import paper you will be refused exit until you pay for the extra number of days.
In my case I was given the impression that the amount I paid was for my full stay, not so... They happily picked a number of days at random for me, made me pay and did not say a word about it only being for a very short period. When trying to exit a month later I was slapped with a bill of 250eu, around 14000 s.p or $340. A very nice dent in my travel budget.
As I understood it, if you have a carnet you are free of the temp. import fee.
Visa at the border
More or less any nationality can get a visa at the border as of lately. The price will vary depending on your nationality, from 16 U.S $ for Americans to 100 U.S $ for Australians.
You will be expected to pay a number of 1$ fees for copying and 'service'. Should not amount to more than a few dollars in total.
For me they would not accept any copy of a document not made by them, maybe you'll have more luck.
During my one month in Syria I only heard of one person being denied a visa at the border, a japanese guy. Should this happen to you, try insisting that it is possible (which it in fact is) or try another border. You will get it sooner or later.
Upon exit you have to pay an exit tax of 550 s.p
For any transaction at the border you need cash and only Syrian pounds, euros or dollars are accepted. They will give you a fair conversion rate.
It is also possible to get a multiple entry visa on the border.
15 days = 30 days
At the border they might ask you for how long you want to stay, if not they will most likely give you 15 days in your visa. However, by some strange rule, these 15 days can be ignored and you have the right to stay 30 days. I, and several other ppl, did this and none of us had any trouble when exiting. Not every border official seems to know about this but their superiors usually do.
If you wish to stay on the safe side it is very straight forward to extend your visa in larger cities.
In Deir Ezzor someone tried to steal my bike one night. They didn't succeed, however they did brake the steering lock and make it impossible for me to move the handlebars forcing me to brake off the rest myself.
What was really annoying about this whole experience was the Syrian attitude to it. Out of collective shame they will happily deny that something like this is at all possible in Syria. Both in Deir Ezzor and Palmyra I was refused parking the bike inside as it was 'unthinkable' that someone would steal it. Mentioning the attempted theft did not help, it was still unthinkable, Syrians do not steal.
However nice the average Syrian might be, make sure you park your bike inside, insist on it.
Be careful with the police
I really don't think this part applies to any one not Syrian but it is still an 'interesting' story.
In Aleppo an Italian guy had his computer and money stolen by one of the hotel staff. The guy was caught on the security camera and taken to the police. The police were very rough with the guy and when left alone with him they actually raped him, unknowingly witnessed by the Italian through a window.
This is a second hand story told to me by the Italian guy so I can't confirm if it is true or not.
Ok, that was a bit long winded but I hope someone can have some use of it.
Also remember to check the weather reports depending on what season you visit Syria. I got caught in my first ever full on sandstorm and it was very scary indeed. Bike and me blew off the road, the sun blacked out and 3 weeks later I am still trying to get the sand out...
//Best of regards from Fredrik and Dersu.