This is a post taken from http://www.thaianxiety.com/scams.asp

Motor Cycle Rentals
From an article in Pattaya City News & discussions on Thai Visa

A foreigner will rent a motorbike and will sign a contract. He or she will park the bike outside of their hotel overnight and the next day the bike is gone.

They contact the rental company who inform them that they must make a report of the theft at the Police Station. This is then followed by a demand for money to cover the cost of the bike from the rental company.

In the cases we have heard about, tourists have been forced to hand over between 40,000 and 50,000 Baht otherwise the company will pursue the case with the Police.

We are sure that most bike rental companies who operate here in Pattaya are honest and law-abiding and this relates to only a small number of dishonest bike renters. In each case that we have heard about, the bike does not possess any form of insurance and the contract contains a clause that the hirer is liable for all costs in case of damage or theft.

After the case has been cleared, the bike will be mysteriously returned to the rental company and the money paid by the foreign tourist is not returned. To avoid this happening to you, we would like to suggest the following:

Only rent from reputable companies.
Ensure that the motorbike is correctly insured to cover damages and theft.
Check the contract for small clauses which could leave you liable for all costs relating to damage and theft by third parties.
Try and avoid giving rental companies your Pattaya address.
Buy a strong padlock and chain. Lock the bike away securely
If you feel you have become a victim of such a scam, please contact the Tourist Police on 1155.