I did a little more research before this trip and heard good things about Angkor Motorcycles in Phnom Penh. Their motorcycles are known to be road worthy and properly maintained. Furthermore, they promised to put working odometers on all their bikes. Seeing that this trip might get a little tough, I decided that it is better to spend the extra money. Actually, their rental rates were just slightly above that of Lucky! Lucky!. At US$9 per day for Honda Degree 250, it was definitely affordable.
To my pleasant surprise, Angkor Motorcycles provided me with a basic set of bike tools, which would come in helpful if my motorcycle is to break down. I also requested an additional screw driver to mount my Garmin GPS receiver which was provided with no questions. However, I was slightly disappointed when I found out only after riding for 10km that the odometer was not working. I rode back to the shop for repair. No big deal I guess, I was not in a hurry and it was partly my fault for not checking earlier.