Riding a Motorbike through Thailand

Very similar to vietnam you may have to pay "tea money" to the local officers normally for not wearing a helmut approx 400 bt , less likely to be stopped if wearing one . Insurance is available in most banks for about 2500 bt. Well worth it if you should have an accident especially caused by an other uninsured driver. Thais are some of the worst drivers in our solar system , proceed with caution and enjoy your travels .
Cheers
      Terry.

If you are considering Laos then I suggest you check out this forum www.gt.rider.com for information about motorbike travel,through South East Asia.
There are temporary import / export papers you will need along with Lao insurance.

Great place for bike touring.

If you have a valid International license for a motor cycle you are not supposed to be ticketed. That license may be valid for 30 days in country, I'm not exactly sure. Not wearing a helmet is the fastest way for a Farang to get stopped at a check point.

I agree with the suggestion to check out gt.rider but I don't get why you insist on breaking the rules and riding without a license or insurance.  In the very least I hope you won't be back here asking for sympathy when you get yourself in trouble.

That said, northern Thailand has some really great roads but I found a bigger bike makes the climbs and the long distances a lot easier.

I am working in Chiang Mai. I bought one motorcycle Honda 125 CC. The motorcycle rental fees is higher, round about 3000 Baht per month. In here, if you want to ride the motorcycle, please take the helmet. Sometimes, the traffic police asked for driving license and  wheel tax. If you don't have, please ask to embassy of your country in Thailand. They can make for that. If not, when the police checked you have to be fine Baht 200 and above.

If you survived in Vietnam, Thailand will not be much of a challenge!
Just keep you defensive driving habits. Anything can happen, but nobody will try to kill you knowingly.

Bribes used to be in the range of 300-400 THB a pop. But lately the police has been extremely friendly with me. Just check my doc and let me go.  (Now I have a Thai driving license  and all ). 125 cc is quite common in Thailand. In fact the trend is to bigger bikes.

Be aware that motorcycles are not allowed in the Expressways / Tollways. Set your google nav to avoid them. You will be caught for sure. Whether they fine you or not, depends. But in the best case you will have to wait for an official vehicle to escort you to the next exit, which is a drag.

Finally: you will find wonderful roads in Thailand. Better off the beaten track. National Parks, for example. Beautiful scenery, well kept roads, no traffic, enjoyable bends and up and downs.

Have a good time!